Directoraat-Ceneraal Rijkswaterstaat
Directie llrrelmeergebled
Intern rapport
Roofvogels in de ~ederlandse
wetlands 10: Energie verbruik
van dd en 9 9 nestjongen bij
de Bruine Kiekendief (Circus
Aeruginosus).
door B.J. Riedstra
Ministerie van Verkeer en Waterstaat
Directoraat-Generaa1 Rijkswaterstaat
Directie Usselrneergebied
directie IJsselrneergebied
bibliotheek
Intern rapport
Roofvogels in de Nederlandse
wetlands 10: Energie verbruik
van dd en Q Q nestjongen bij
de Bruine Kiekendief (Circus
Aeruginosus).
door B.J. Riedstra
Interne rapporten zijn in principe interne
cornrnunicatierniddelen; hun inhoud varieert
sterk en kan zowel betrekking hebben op een
weergave van cijferreeksen, als op een discussie
van onderzoeksresultaten.
Smedinghuis
Zuiderwagenplein 2
Tel. (0320) 299111
Telex 240115
Telefax (0320) 234300
Referaat
Het rapport wat voor U ligt beschrijft het energie verbruik van vrijlevende nestjongen van
de Bmine Kiekendief. Met behulp van dubbel gelabeld water zijn de dagelijkse energie
uitgaven van zowel mannetjes als muwtjes gemeten, om zo tot een schatting van de
kosten van het grootbrengen van beide sexen te komen. Onderzocht is of deze kosten de
afwijkende sex ratio, die bij deze soort voorkomt, kan verklaren.
Dit onderzoek is eedaan als onderdeel van het doctoraal curriculum aan de
Rijksuniversiteit Groningen. Het onderzoek w e d uitgevoerd bij de werkgroep
Chronobiologie van de faculteit Gedragsbiologie 0.1.v. Cor Dijkstra en Serge Daan.
Het onderz&k valt in het kader van hit onde&oeksProject
betekenis v&
Grootschalige wetlands in Nederland voor roofvogels', een samenwerkingsproject van
Rijkswaterstaat directie Flevoland en de Rijksuniversiteit Groningen.
'~e
Dankwoord
Hiermee wiI ik de volgende mensen bedanken die het mogelijk gemaakt hebben dit
onderzoek te verrichten en te voltooien. Ten eerste is dat Cor Dijkstra die zowel in het
veld als tijdens de uitwerking de zin van de onzin wist te scheiden en onder wiens leiding
ik zeer veel geleerd heb. Dan is daar Serge Daan in wiens groep dit onderzoek werd
vemcht en die samen met Rijkswaterstaat leiding geeft aan het project 'De betekenis van
grootschalige wetlands in Nederland voor roofvogels. Samen met Serge wil ik hierbij de
hele Chronobiologie groep bedanken voor een fijne en leerzame tijd, Ido Pen en Karen
Krijgsveld met name, voor hun vruchtbare comrnentaren, data en software. Tevens wil ik
Henk Visser van CIOlchronobiologie voor alle DLW analyses en Rijkswaterstaat dir.
Flevoland bedanken voor de Financiering van het Project. Ten slotte wil ik Staats
Bosbeheer en het Ministerie van Defensie bedanken voor het vrij mogen werken in het
mtuurgebied de Lauwersmeer.
In het kader van het ondenoeksproject "De betekenis van grootschalige wetlands voor
roofvogels" zijn de volgende rapporten verschenen:
Beemster, N. & C. Dijkstra (1991). Roofvogels in de Nederlandse wetlands: 1. Variaties
in voedselaanbod: woelmuizen. Intern rapport 1991-21 lio. Rijkswaterstaat, diiectie
Flevoland, Lelystad.
Vogt, D. (1994). Roofvogels in de Nederlandse wetlands: 2. De Bruine kiekendief;
demografie en terreingebruik. Intern rapport 1994-1 lio. Rijkswaterstaat, directie
Flevoland, Lelystad.
Beemster, N. (1994). Roofvogels in de Nederlandse wetlands: 3. Aantalsverande~gen
van roofvogels en uilen in de Lauwersmeer in de periode 19691'70 - 19901'91. Intern
rapport 1994-2 Iio. Rijkswaterstaat, directie Flevoland, Lelystad.
van Rijn, S . & J. Winter (1994). Roofvogels in de Nederlandse wetlands: 4. De Bruine
kiekendief; terreingebruik en jaagsucces in de Oostvaardersplassen in 1992. Intern
rapport 1994-10 lio. Rijkswaterstaat, d i i t i e Flevoland, Lelystad.
Dijkstra, C. & M. Zijlstra (1994). Roofvogels in de Nederlandse wetlands: 5. De Bruine
Kiekendief: mortaliteit en migratie. Intern rapport 1994-21 lio. Rijkswaterstaat, directie
Flevoland, Lelystad.
Krijgsveld, K. (1994). Roofvogels in de Nederlandse wetlands: 6. Energiebehoefte van
88 en 9 9 nestjongen van de Bruine kiekendief. Intern rapport 1994-39 lio. Rijkswater
staat, dimtie Flevoland, Lelystad.
van Rijn S., N. Beemster & M. Zijlstra (1995). Roofvogels in de Nederlandse wetlands:
7. Roofvogels in de Oostvaardersplassen in de periode 1982183 - 1993194; effecten van
beheersmaatregelen. Intern rapport 1995- 7 lio. Rijkswaterstaat, diictie
Usselmeergebied, Lelystad.
Beernster, N., & S . van Rijn (1995). Roofvogels in de Nederlandse wetlands: 8. Variatie
in jaagsucces van op veldmuizen jagende roofvogels. Intern rapport 1995-14 lio.
Rijkswaterstaat, directie Usselmeergebied, Lelystad. '
Dijkstra, C., & M. Zijlstra (1995). Roofvogels in de Nederlandse wetlands 9: Aantalsont
wikkeling en broedsucces van de B ~ h kiekendief.
e
Intern rapport 1995-18 lio. Rijkswa
terstaat, directie Usselmeergebied, Lelystad.
Riedstra, B. (1995). Roofvogels in de Nederlandse wetlands 10: Energiegebruik en
mortaliteit van 88 en 99 nestjongen van de Bruine kiekendief. Intern rapport 1995..lio. Rijkswaterstaat, diictie Usselmeergebied, klystad. Het rapport wat voor u ligt,
Werkdocumenten in het kader van het roofvogelproject::
A. Dulos. 1990-10 1iw
J. Prinsen. 1991-3 liw
R. van Hoeken. 1992-1 liw
R. van L i b u r g en E. Aman. 1993-12 lio
1. Postema en P. van Putten. 1993-17 lio
A. Hendriks en S. Puijrnan. 1993-22 lio
7. L. Jobse. 1994-14 1io
1.
2.
3.
4.
5.
6.
Contents
Nederlandse sumenvatting (Dutch &stmet)
Introduction (I)
Methods
Results
(11)
(ZZZ)
- A. Growth
- B. Daily Energy expenditure
- C. Energy intake and energy budget
- D. Energy intake during the nestling period and its relation to sex ratio
sex ratio
Discussion (N)
- 1. Growth
- 2. Daily Energy Expenditure
- 3. Energy intake
- 4. Energy intake during the nestling period and its relation to sex ratio
- 5. Concluding remarks
References (V)
- Appendii 1: Mean body mass of surviving young
- Appendix 2: Characteristics of DLW individuals
- Appendix 3: Individual mean isotope counts
- Appendix 4: Clirnatal conditions during the measuring period
- Appendii 5: Individual GEI estimates
- Appendix 6: Nest site distribution in the Lauwersmeer area
Sex ratio theorie voorspelt dat in soorten waarbij de ene sexe goedkoper is om te
produceren dan de andere (sexueel dimorfe soorten), de goedkopere (kleinere) sexe aan
het eind van de ouderlijke verzorgingsperiode in de meerderheid zal zijn. De Bruine
Kiekendief is een soort waarbij de mannetjes kleiner zijn dan de vrouwtjes. Tevens is uit
populatie onderzoek gebleken dat er meer mannetjes uitvliegen dan vrouwtjes. De vraag
waar in dit rapport op ingegaan wordt, is of deze kleinere mannetjes daadwerkelijk
rninder kosten om te produceren dan vrouwtjes. Tevens werd onderzocht of deze kosten
de gevonden sex ratio bij uitvliegen kan verklaren.
Om deze vraag te onderzoeken werden de dagelijkse energie uitgaven (DEE) van 8 paren
nestjongen van de Bruine Kiekendief m.b.v. de zwaar water methode gemeten. Een paar
bestond uit &n mannetje en Ctnvrouwtje uit 65n nest. De jongen werden gemeten op een
leefijd van ongeveer 24 dagen. Aan de hand van deze gegevens werd een schatting
gemaakt van de totale kosten van het grootbrengen van zonen en dochters. De
belangrijkste conclusies:
1) Een dochter had op een leeftijd van 24 dagen altijd een hogere DEE dan haar
broer(tje). Gemiddeld was de DEE 1.25 maal zo hoog voor dochters ten opzichte
van zonen. Het verschil in DEE werd vrijwel geheel verklaard door het verschil in
lichaamsgewicht (BM). Per gram BM was er geen verschil in DEE.
2) De totale dagelijkse hoeveelheid gegeten energie (GEI), op een leeftijd van 24
dagen vergeleken binnen nesten, was hoger voor dochters. Ook dit werd voor het
grootste gedeelte verklaaq door de gewichtsdirnorf~e.
Het verschil in voedselopnarne tussen zonen en dochters, zou de afwijkende sex ratio bij
het uitvliegen kunnen genereren. Een voorlopig model (Dijkstra pers comm.), waarin het
verschil in voedselbehoefte als maat voor de kans op mortaliteit tussen broedsels van
verschillende samenstelling (aantal mannen en vrouwen) gebruikt wordt, lijkt dit te
bevestigen. Het blijft echter de vraag of er bij het uitkomen van de eieren een afwijking
aanwezig is in de sex ratio. Met behulp van moleculaire technieken wordt nu geprobeerd
om de sexes van pas uitgekomen (gestowen jongen) te achter halen.
I. Introduction
The question of how individuals should allocate their reproductive resources to their sons
and daughters has delivered rwo main tenets. F i t , Fisher (1930) argued that diploid
dioecious species pass, under autosomal inheritance, half of their genes to an offqpring. A
zygote inherits half of its genes from the mother and half from the father. This one
mother-one father symmetry generates a frequency dependent natural selection on sex
ratio, resulting in an evolutionary equilibrium (ESS) where half the reproductive resources
are devoted to daughters and half to sons.
Second, violations of this symmetry can occur if under a certain set of conditions, natural
selection favours individuals that shift more resources to one sex (Chamov 1993).
Three types of violations have been well characterized: 1) population structure, 2)
individual circumstances (Trivers and Willard 1973) and 3) time of year (Dijkstra 1988).
Thus, sex ratio deviations within populations are expected, when in terms of fitness the
profitabilities between sons and daughters vary predictably.
In avian populations, sex ratios at birth rarely deviate from unity (Glutton-Brock 1986).
Sex ratios at birth are difficult to determine. Most sex ratio studies on birds have
concentrated on the secondary sex ratio (i.e. the sex ratio at the end of parental care). An
exception to (secondary) sex ratios that are at unity are, sex ratios measured in raptor
populations (Olsen & Cockburn 1991, but see Krackow 1993). These biased sex ratios
might be an effect of the reversed sexual size
(RSD; 9 P are bigger than 6 8 )
present in most raptors. In energetic terms, one would expect that birds, growing bigger
(9 9 ) have higher energy demands than birds that grow smaller (dd). But, in a study on
the food intake of Sparrow Hawk broods (Accipiter nisus), a diurnal raptor with a
pronounced RSD, Newton (1978) found no significant differences in the total food intake
between siblings of different sex, over the total period that young were in the nest.
Males, however, developed plumage and body skills more rapidly than females and,
subsequently, left the nest earlier than their female siblings. There has been no record of
a skewed sex ratio in this species, yet. in order to find sex ratios signifcantly deviating
(but not too much) from unity, huge sample sizes may be required. Not many studies with
sample sizes big enough to detect skewed sex ratio's have been published. A study on the
Marsh Harrier (Circus aeruginosus), however, showed that in two Dutch populations, the
sex ratio at fledging was significantly male biased. The number of male fledglings relative
to the total number of fledglings was 54.8% (Zijlstra et al. 1992).
This male biased sex ratio does not force us to reject Fisher's theory. The Marsh Harrier
is a diurnal raptor that also shows a RSD. Males being the smaller and supposedly
cheaper sex to produce, equal allocation of resources to both genders would predict a
biased sex ratio in favour of males. Krijgsveld (1994) showed that in terms of food
intake, female Marsh Harrier nestlings were more expensive to raise than males were.
Krijgsveld's study was conducted in the laboratory, where food was ad libitum.
The aim of this study is to estimate the costs of rearing free living male and female
Marsh Hamer nestlings that have to compete for a l i i t e d amount of food. And to study
how and if these costs reflect the secondary sex ratio.
11. Methods
This study was conducted in the Lauwersmeer area in the summer of 1993. Data on
growth of Marsh Harrier nestlings were collected from 1990 to 1994 from all ages during
nest visits, using a 50gr and a lOOOgr pesola spring balance. Weight measurements were
rounded to the nearest .25 grams, 1.0 gr resp. All data points on growth were treated as
if they were independent of each other. Age was exactly known (rounded to day) because
of a high nest visiting frequency during the hatching period. In case, age was not exactly
known, age was estimated by wing length pack calculation). The sexes of individuals
were determined by measuring the foot length when individuals were at least 20 days old
(Zijlstra et al. 1992). Logistic growth curves were fitted using SPSS/PC+. The model
used for logistic growth:
Where BM = Bodymass (prams), A = asymptotic weight (grams), k = intrinsic growth rate, Age = age of
an individunl in days and b is the age at which the point of infledon is reached.
DEE was measured using DLW (Lifson & McClintock 1966) during the summer of 1993,
from 14/06 to 18/07. 8 pairs of birds were measured. A pair consisted of one female and
one male from the same nest. This painvise design was chosen to correct for varying
environmental conditions and possible genetic differences between birds of different nests.
Birds were selected on age, sex, and sequence. Because Marsh Harrier nestlings hatch
asynchronously two succesive nestlings within the sequence of hatching were selected,
both as close as possible to the age of 24 days. Individuals were also selected on health
(i.e. obviously growth retarded buds were not used for the DEE measurements). None of
the pairs had a bigamous father (as frequently is the case in the marsh harrier). The age
of 24 was chosen for several reasons: growth rate had slowed down (differences between
the sexes are minimal), gender could be determined, activity was relatively low, and they
could be recaptured.
The selected individuals were injected intraperitonially with Doubly Labelled water
(DLW): 6 d 0.851111, ? ? 1.0ml. The isotope ratio of the injected DLW was: 11.7889
gram H,'80 (90.79AP), 5.7562 gram ZH,O (99.9 AP). The initial blood sample was taken
one and a half hours after injection. The final blood sample was taken approximately 48
hours later (varying from 47h10' to 48h39'). Blood samples were taken from the vena
ulnaris, by perforating this vein and sucking the blood directly into capillary tubes (glass),
from either the cup of the needle or from the dry skin. On days of bad weather, blood
samples were taken by fmt drawing blood into a syringe. Four additional samples (from
two untreated 66 and 4 9 ) were taken to measure the natural occurance of 'H and "0
(background samples). The ends of the capillary tubes were sealed using a propane
burner. A minimum of six tubes were filled from which two or four were eventually
analyzed. The samples were stored at 5°C within 8 hours. In january 1994 the samples
were analyzed on their isotope contents (see appendix 2&3.) at the 'CENTRUM voor
ISOTOPEN ONDERZOEK' of the Rijksuniversiteit Groningen. DEE and water influx
were calculated using the softwareprogram 'D20l.exe (developed by I. Pen). A
respiration coefficient (RQ) of 0.72 and energetic equivalent of lmol
these calculations were taken from Gesseman & Nagy (1988).
Statistic calculations were performed using Statistix 3.1.
4 of 19.8k.l used in
1
1
i
111. Results
A. Growth
Daily body weights of nestlings were recorded during nest visits and pooled for the years
1990 to 1994. Data points collected from the same individuals were treated as
independent data points. From this set, a selection was made that contained only
individuals that survived until the oldest chick was about 35 days or older (just before
fledging). From this selection a logistic growth curve was calculated (see methods) and
displayed in figure 1 (see appendix 1 for data on which the curves are based). The
parameters that characterize the curve are displayed in table 1.
JLW:
I
figure I . Mean daytime body weights of Marsh harrier nestlings in the field. The open dots represent the
females, the closed ones tlie males. The Lines represents the logistic growth model. The area between the
stippled l i e s indicate the age period at which DLW measurements were cnrried out. 'Ibis p p h shows dl
the males and females that survived until the oldest chick in the nest was 35 days or older (Appendix 1).
Upto the age of 15 days, there was no noticeable difference in bodymass nor growth rate
between males and females. Possible differences in energy demands in this period, are
expected to be relatively small or absent. Between age 15 and 25 the growth curves were
drawn apart in spite of the big spread in mass in each group. Different energy demands
could be expected. After this period, growth rate levels off and there was a clear
difference in body weight. In this period possible differences in energy demand are
expected at least, as a result of the clear dimorphism in body weight, due to maintenance
(of more tissue). It is not clear from these data, if at the end of the nestling period, the
nestlings decrease in body weight as was the case in the kestrel (Falco t i m c u l u s ) for
example (Dijkstra 1988).
Table I. Logistic growth model parameters: A is the calculated asymptotic weight (grams),k is the intrinsic
growth constant (per day) and b is the point of inflection h days (point with the fpdest growth). N is the
number of data points and R
' is the correlation coeflieient.
males
females
564.1
734.2
0.2263
0.2222
13.4
14.8
450
439
0.976
0.975
Males reach the age of maximum relative growth rate (b) 1.4 days before females. The
relative growth rate at this point is also slightly higher. As a result, they reach asymptotic
bodymass earlier. Maturation in males is faster than in females (i.e. juvenile plumage in
the DLW measuring period is better developed in males, consequently, at the age of 35
days they are more difficult to catch than females because of higher mobility).
The DLW individuals increased on average slightly more in body mass than the logistic
growth equation predicts. On day 24 the c w e predicts a growth rate of 16.6 grams per
day for females and 9.5 grams per day for males. Thus, there were no indications of
deviant growth due to the experiment. The measured growthrate of the DLW individuals
are shown in table 2.
B. Daily Energy Expenditure
Table 2. gives an overview for both sexes of: mean age (mean of age at injection and
taking the f m l sample), number in sequence, bodymass, growthrate, and measured DEE
per day. Per individual these parameters are displayed in appendix 2.
Table 2. Overview of the growth parameters of the seletted nutllngs used for DLW measurements. Both
groups consisted of 8 individuals. AU parameters are means of the group and are given with their standard
deviation of the mean. Age is given in days, bodymass in grams, growth in grams per day, and DEE in icJ
Per day.
sex
sequence
age
bodymass
growthrate
DEE
There were no significant differences in age, sequence, and growth between males and
females. Females were significantly heavier than males (table 3) . The mean DEE of the
females is 1.25 times higher than that of the males. Pairwise, all females had a higher
DEE than their male siblings Vgure 2 All points are above the line Y=X). In spite of the
big overlap in DEE a groupwise comparison also showed a significant difference. The
DEE of females and males are displayed pairwise in figure 2.
Table 3. Statistical p-values of paired and unpaired tests. For the difference within pairs (paired), the
Wileoxon signed rank test (WSR) was used. For the difference between the sexes (unpairedlgroup
comparison), the One-way analysis of variance (oneany AOV) test was used. From the WSR test the one
tailed p-values are shown. The rust column represents the tested parameter. A star (*) indicates a
significant difference.
Sequence
Age
bodymass
growth
DEE
paired
group
0.2734
0.0781
0.0039
0.1562
0.0039
0.5899
0.0961
0.0000
0.5456
0.0300
*
*
The difference in DEE could for a large part be explained by bodymass. Per gram
bodymass (mean bodymass: bodymass at the time of the initial blood sample and at the
time of the final sample divided by two), the DEE of males did not differ from that of
females: 1.08f 0.16 kllgram (WSR, p=0.4219: one-way AOV, p=0.9028). Because
males and females did not differ in DEE from each other per gram , the sexes were
pooled. A logarithmic transformation was performed on bodymass and DEE. The model
forces the line through the origin. DEE increased as a power function of bodymass:
DEE=16.m37*BM"~"S(lin.regr. p=0.0046 R2=0.448).
DEE male (kJIday)
?
2. Daily Energy Expenditure per pair. The dots represent the DEE of a female nestling against the
of her male sibling. The open circle represents the group means. The line Y=X represents the points
i+nereDEE,,=DEE,,. The numbers in the graph indicate the escribed nest numbers (see appendix 2&6).
DEElmean BM male (kJlgram)
figure 3. DEE per gram per pair. The dots represent the Daily Energy Expenditure per gram body weight
of a female nestling against the DEE per gram body weight of her male sibling. The open circle is the
group mean. 'Ibe b e (Y=X) represents the paints where DEEIBM,,=DEEIBM,,. The numbers indicate
the ascribed nest numbers.
The differences in DEE between pairs might be caused by environmental factors
(temperature, rainfall, windspeed etc.). Data on c l i i t a l conditions and date of
measurements are displayed in appendix 4. The climatal measurements were obtained
No relations of DEE with the displayed climatal
from the airport of Groningen 0 .
parameters were found. Only the amount (mm's rain) and duration of rain seems to have
an effect on DEE: duration and amount becomming longer or larger, DEE becommes
higher.
Table 4. Statistical pvnlues of least squares bear rcgnssion of DEE on climatd factors. m e Cirst column
displays the different parameters. The second and third display the pvnlues of DEE vs cLimatal
parameters of dd and 9 9 seperatly, and the fourth DEE of 86 and 9 9 together.
Windspeed
mm's rain
hours rain
temperature
humidity
DEE88
DEE99
DEE,,,
0.5061
0.4504
0.3704
0.8943
0.3636
0.4170
0.0911
0.0721
0.9613
0.7898
0.3388
0.1341
0.0988
0.9032
0.6620
C.Energy intake and energy budget
Assuming that the H20 influx calculated with the D201.exe program can only come from
prey (food intake), and not from additional drinking, the amount of prey eaten, and Gross
Energy Intake (GEI) can be estimated:
Method I.H,O influx
1
GEI = H,O-
* 18 *
I
[%H,O],,
* E,, (In Wlday)
Where H,Om, = calculated in moles, 18 = the molecular weight of H,O
of the food eaten and E, is the energetic content (kJlgmm) of the food.
,[%H,O],
(eq.2)
is the watercontent
The foodspectrum of the Marsh Harrier is very broad. Many different prey remains were
found on nests (Zijlstra & Dijkstra in prep.). The exact composition of the food intake of
the young during the DLW measurements was not known. In order to calculate the
amount of food eaten, I assumed this to be one day old cockerels. One day old cockerels
had a watercontent of of 0.7562 and a energetic content of 26.24 kJ per gram dry weight
(Krijgsveld 1994). This means that the energetic content of 1 gram fresh weight = 6.397
kJ [26.24*(1-0.7562)l. Which is roughly the same as the energy content of 1 gram of
common vole, Microrus arvalis (Masman 1986). the main prey type of the Marsh Harrier.
The mean GEI (f sd) of the males was 1216.6 f 225.78W (n=8) and of the females
was 1456.5 f 162.57kJ (Figure 4A). The GEI was painvise (WSR,p=0.0117) as well
as groupwise (One-way AOV, p=0.0287) significantly higher in females.
Assuming an assimilation coefficient of 0.71 (Krijgsveld 1994), the metabolizable energy
intake could be calculated (0.71*GEI). By subtracting DEE and dividing the total by
growth, the amount of energy needed to grow one gram in body weight could be
calculated. From the total set, only the individuals that had positive growth were used
(n=12). For males and females this was 21.20 f 24.18 and 14.38 f 17.52Wgram resp.
These costs did not differ from each other (One-way AOV, p=0.5239). The cost of
making 1 gram of tissue was, therefore, 17.79 f 17.44 W.
Another way of calculating the GEI, is to assume a certain energetic density of the tissue
(&) of a growing bird (and a assimilation coefficient). The mean &, according to
Ricklefs (197411981) is about 7W. The assimilation coefficient was assumed to be the
same as in laboratory conditions, 0.71. GEI can be calculated as follows:
,.
Method 2. Ed.
GEI = DEE
+ Growth * 7 (in
kJlday) (eq.3)
0.71
Where GEI is calculated in Wlday, DEE is the me~surrdDEE in the fldd (IJ), growth is the mean growth
in grams per day over the measured period (DLW), and 0.71 is the asnked ayimihtion coemcient.
In the latter method, The GEI of the females was estimated to be 1172.5 f 216.5 and
that of males 922.6 f 300.4kJ (Figure 4B). This was much closer to the laboratory
measurements than the estimates from the former method. Males had a lower GEI than
males raised in the lab. This is partly due to the fact that two individuals suffered loss of
body weight (The data of the individual animals from both methods are given in appendix
5.), a fact that method 1 does not take into account. The differences in GEI calculated by
the method 2 were significant within pairs (WSR, p =0.0078). A group-wise comparisson
reveals that on average females had no higher GEI than males (One-way AOV,
p=0.0771).
2000 -
q
1500
-
1000
-
Y,
I
-m
W
Q
2000
7
'
1500 -
5
m
-
500
I000
1500
2000
GEl male (kJ)
figwe 4. Comparison or GEI between females and males. Ench do& symbol represents a pair. The open
symbols represents the group means. A) (triangles) GEI calculated via the H,O influx. B) (squares) GEI
calculated via G.m e line in each graph represents the points at which GEI,,=GEI,, (Y=X).
From the measured and calulated data an energy buget was consaucted. Figure 5 gives an
overview of the energy budgets of males and females calculated according to both
methods.
female male
.
female male
Figure 5. Energy budget of a male and a female Marsh Harrier nestling at the age of 24 days. The total
lenght of the Bars &&ate tbe GEI. The nhite part is lost due to imperfect digestive efficience
(Assimilation coefficient of 0.71 was assumed). The striped part is than the MEI, from which the black
part k used as DEE. The two bars on the lef? hand side, are the bugets calculated via the H,O influx. The
bars on the right hand side the bugets calculated via E,,,.
In both methods the GEI per gram bodymass did not differ between the sexes: - H,O
influx, 2.25 f 0.29kJlgram (WSR,p=O.2734: one-way AOV, p=0.5988) - &, 1.76 f
0.40 kJlgram (WSR,p-0.4727; one-way AOV, p=0.8650). The data of the DLW
individuals are displayed in figure 6.
GEllmean EM male (kJlgram)
Pgun 6. Comparison of GEI per p m bodym~rsb e m n males and females. Each dosed symbol
repents a
The open symbob reprrP1 I*p u p m m . A) ( l ~ h d e s G
) E V * d m celeulnted
via the H,O influx. B) (squares) GEU*dym~rscalculated via &. l k e line in ench m p h n p w the
points at which GEI/bodyma~~~=GEvbodym~rs~~
(Y=X).
e.
D.Energy inrake during the nestling period and the relation to sex ratio
In this part. I try to estimate the total energy intake (G&)
of nestlings until fledging,
and GEI,, during the period of parental care, in two models using both methods of
estimating GEI.
model 1: In this model it was assumed that the difference in the ratio of GEI calculated
at the age of 24 days was
for the field data and the GEI measured the lab (GEI,IGEI,)
valid for the total period that paren6 provide parental care. The nestling period was
assumed to be 36 days and Krijgsveld (1994) measured a period of parental care of 70
days in the same population this study was conducted.
Thus: ( G E U = GELIGEI,
* GEI,:,
,
(in grams)
(eq.4)
model 2: (method 1) GEI increases with bodymass (GEI=10".76"3*BW8503
lin.regr.
p=0.0050, R2=0.4419) in the sample set. In this model it was assumed, that the
relationship between GEI and Bodymass (power function) calculated for individuals at an
age of 24 days is applicable for the total period that parents provide parental care. The
total energy intake can be calculated using the logistic growth curve (see above). The data
on GEI intake and DEE in relation to bodymass are shown in figure 7.
Thus: G E L = , j ' (10°.76Q*BM6.~
dAge (in kJ) (eq.5)
Where
represents the inbegal of GEI as a function of age (x), where x =36 or x=70 days, and BM is
the formula for logistic bodymass curve calculated above.
model 2: (method 1) In the second method of calculating GEI a different approach was
necessary. In section B the relation between DEE and bodymass was calculated. From the
logistic growth curve the growth could be calculated; the derivative of this function. I&
was assumed to be 7kJlgram , Yielding the following equation:
GEL=
,I " [(10°.0U7*~M0~+(growtb * 711 * 1/0.71 dAge (in kJ) (eq.6)
(DEE)
,
Where j represents the intregal of GEI as a function of age (0-36 and 0-70 days), and BM is the logistic
bodymass curve calculated above. m e f i part of the equation represents DEE (section B) + the cost of
growth, which is the MEI. This sum bas to be divided by the mimilation coefticient to yield GEI.
EM (grams)
Figure 7. Relationship of DEE and GEl with bodymass. I b e dosed symbols represent the data points of
the males the open those of the females. The circels represent the DEE data. A) (trinngels) reprrsents the
GEI calculated via the H,O-influx. B) (squares) GEI calculated vin I&,. The fat line in both graphs is the
Kirkwood (1983) equation for m d m m ME1 divided by the asisnibtion coeffident (0.71).
In both models the GEI was calculated over the 1) nestling period and 2) the total period
over which parental care was provided. The first period runs from day 0 to day 36. This
period is the bigger part of the nestling period. Day 36 also coincides with the age, at
which the laboratory birds were put in an aviary. The second period runs from day 0 to
day 70 which is the period from fledging to the end of parental care.
The amount of food eaten on day 24 in the lab by males and females was 936.8 and
1084.2 kJ resp. (Krijgsveld 1994). Yielding a ratio GEIfd1GEI, of 1.3 and 1.34 for
this
males and females resp. via the water-influx method. For the GEI calculated via L,
ratio was for males and females 0.98 and 1.12 respectively. In the second model the GEI
is calculated in kJ. The same conversion factor was used as in the first model (one day
old cockerels have an energetic equivilant of 6.3973 Wgram fresh weight). Table 5 gives
an overview of the results calculated above.
sex Ratio
I
If the GEI representes the costs of rearing males or females, sex ratio theory predicts that
the ratio in costs of raising sons or daughters is inversely proportional to the sex ratio:
number of P? c
ost (eq.7)
number of 88 ' cost of rearing a 9
Table 5. Comparison of lab data and field estimates of total energy intake in grams during the ncctling
period and the total time parental care is provided. The f a two columns give the on average amoturt of
food eaten by a male or female, tbe tbird upwses the ratio between a male and a female for the two
defmed periods. The row Lab, indicates the m m d G U in grnms by Krijgsveld, the rows HZ0-influx
and Energ.dens represent the GEI estimated via the HZO-influx and E,,, method
day 0-70
day 0-36
Lab
model 1:
H2O-influx
Energ.tis.
model 2:
HZO-influx
Energ.tis.
one-8
one-?
6/9
one-8
one-9
3571.8
4323.2
4643.3
3694.9
4666.4
3743.2
8/?
0.826
7252
9136
0.794
5793.1
4835.9
0.802
0.764
9428
7142
12242
10250
0.770
0.697
5500.4
4806.3
0.848
0.779
11509
8106
14073
10669
0.818
0.760
The sex ratio Zijlstra et al. (1992) measured was 54.8% (percentage males). The ratio
expressed as the number of females divided by the number of males is 0.825. The ratio in
GEI between males and females calculated via the water influx method, is in every case
(both models and both periods) closer to the ratio found in the laboratory than the E,
method. Each ratio calculated via the water influx was, in every case closer to the inverse
of the sex ratio.
I
I
I
1) Growth
The logistic growth model (equation 1) used in this report has a good fit (R2= C, 0.98).
The model however implicates that there is an asymptotic weight to which the different
individuals grow. The asymptotic weight is an underestimation of the maximum weight of
an average bud (figure 1). Moreover, at the end of the nestling period the young tend to
lose weight. This means that after the age of about 38 days, the model predicts a higher
weight than measured. The model also doesn't seem to give a good fit in the fmt period
(first six days after hatching). The model tends to overestimate real weight in this period.
Compared to the situation in laboratory conditions (Krijgsveld 1994) individuals in the
field were slightly heavier when they reached asymptotic weight. Weight in the laboratory
situation, however, was expressed as morning weight. This means that the laboratory
nestlings had suffered bodymass loss during the night, and crop and gut were empty.
Weight used in this report was measured during the whole day, centered around noon. It
was likely that they had been fed already. Presumably crop and gut were not empty, and
some food had already been converted to body weight.
Thus, animals raised in laboratory conditions grow bigger. Hence, there must be a limited
amount of food in the field, over which the siblings have to compete. Therefor,
differences in energy requirements between the sexes could result in differential mortality
(Dijkstra in prep). In the DLW individuals variation in daily food supply might have had
a big impact on the bodymass measured at a certain point in time. The 48h period over
which DEE was measured theoretically takes away some of this variation but not
everything. The individuals that suffered negative growth might in fact just be an artefact
of the timiig of the experiment (stochastic events).
From the logistic growth curve we can derive, that males (in the DLW measurements
period) have to grow less of their (sex-specific) asymptotic weight than females have to of
theirs. Males grow in this period 1.5%, and females 2.1 % of their asymptotic weight
(population data). Males could, therefor, be able to allocate more energy to physiological
processes, other than bodymass growth (Richer 1991) such as feather synthesis. At the
age that DLW measurements were taken males were better feathered. Males were also
more able in trying to escape the researcher at day 36 than females.
For a ground breeding bud such as the marsh harrier predation can have a great impact
on their individual success. In 1994, 21 of 40 nests in the study area were lost due to
predators. Some individual breeding birds even lost two or more nests. Since the chicks
hatch asynchronously, it might be advantageous to place the sex that grows (or matures)
faster later in the sequence. Fledging is more synchronized and the total time of the brood
spent in a risky environment is minimiid.
2) DEE
DEE in females was 1.25 times higher than in males, this diierence could be explained
by the weight difference between the sexes. Females had a higher DEE because they were
heavier (per gram bodymass there was no difference). Moreover, DEE correlated with
body weight. Taking aside, the fact that sex and condition (body weight) effects on DEE
are not the same as age I treated the DLW-individuals bodymasses as a measure of age. I
then used this to extrapolate this correlation over the total nestling period. The resulting
power function relationship takes away lot of the variation and resulted in a more realistic
value at hatching than a linear approach. In doing so, DEE is probably overestimated in
the early stages of life, because parents can brood the young and they are less active than
in the measuring period. Activity increases and brooding decreases toward the moment of
fledging. Young start to explore the immediate surround'mgs of the nest and start to train
flight muscles.
There are two additional costs during development that are, not related to bodymass
growth, easily overlooked. The fmt, is the replacement of the fmt down in the second,
and the second is the change of the second down into the juvenile plumage. The DLW
measurements took place during the second transition, where the males tended to be better
feathered (more matured) than the females. Adult females do not only have a higher
weight, they also have a longer wings (Glutz van Boltzheim 1971). Females have to
produce more costly feather material than males have to. This increases the difference in
energetic demand between males and females after fledging.
The assumed RQ and energetic equivalent (Gesseman & Nagy 1988) deviate from those
measured in the lab. Due to some problems in the measuring equipment in the lab, it was
not possible to use lab data. RQ is dependent on the food digested: a difference in food
composition and intake can result in a different RQ. When raising the RQ, DEE
decreased, resulting in more energy that can be allocated to growth. A lower RQ, had the
opposite effect. Changing the energetic equivalent of 1 moI0, has the exact opposite
effect of RQ. None of these parameters had influence on the measured water influx.
3) Energy intake
According to Witkofski (1986) nestlings only drank water nearby nests on hot days. The
nests that were used to measure DEE were all situated in dry reedbeds (no water nearby)
and temperatures were not extremely high (although the microclimatal conditions on the
nest site might very well be different). Different possibilities in the way that water could
be ingested are: via morning dew or rain (there is no evidence that they drank in this
way), from wet prey items, or the water content of the prey. Food is not always taken to
the nest dry. Additional water might be ingested through the condition and type of prey
that is delivered. Taking all this aside, and assuming that a11 water was ingested through
food: on the (average) age of 24 days females ate 1.2 times more than males. Both sexes
ate about 1.32 times more than the animals situated in the lab (H20-influx method
(eq.2)). When assuming a certain assimilation coefficient in this method. The obtained
results can not explain why birds that suffered a loss in bodyweight (negative growth) still
had a higher MEI than DEE.Water released via burning of endogenous tissue are
probably measured as water influx. Another explanation is: birds that are supposed to
grow but suffer bodymass loss, might physiologically spoken be different buds. An
addaptation of the digestive efficiency might result in a MEI higher than DEE. If the
allocation of energy to feather synthesis is more important than to body weight growth,
this could still result in a loss of body weight.
Another way of calculating ME1 and GEI is assuming a certain E, and assimilation
efficiency (eq.3). Klaassen (chapter 3, 1992). found in Terns (Sterna spec.), that energy
density of tissue increases with decreasing bodywater content. The bodywater content
decreases with increasing relative bodymass (maturation). The production costs of body
tissue is the product of energetic density and synthesis efficiency. For the Marsh Harrier,
percentage bodywater is known (appendix 2). The bodywater percentage of Marsh Harrier
as a function of relative bodymass, lies well above the line of the terns. The measured
chicks are at about 90% of their predicted asymptotic weight, and have bodywater
percentage of 76%. Due to lack of accurate data on the Marsh Harrier, I assumed the
energetic density of 1 gram bodytissue to be 7kJ. In this method, the birds that suffered
weight loss have a lower ME1 than DEE. Still, all the females had a higher GEI than
there male siblings.
The GEI estimated via the water influx is closer to the maximum GEI (Kirkwood 1983)
than the GEI estimated via the &-method. On the one hand, the first method is an
overestimation of GEI because of reasons mentioned above. On the other hand, the latter
method of estimating GEI might be an underestimation because energtic density of the
tissueis higher. Or visa versa lower.
4) Energy intake during the nestling period and the relation to sex ratio.
In the lab the cumulative energy intake was measured exactly for the period 0 to 36 days
(Krijgsveld 1994). The estimation of GEI from day 36 to 70, however, was estimated on
the basis of two points. The energy intake in the field could only be estimated under a set
of assumptions. In the first model (equation 4). the GEI ratio (fieldllab) at the time DLW
measurements were taken, was assumed to be constant during the total period. This might
well not be the case. In the lower age region, the conditions for nestlings in the field
might well approach lab conditions. A brooding female can to a certain extent regulate
the temperam of the chicks. In this case the cumulative energy intake of the nestlings in
the field was overestimated. From the time that females leave the nest for longer periods
(later in the nestling stage) the conditions will change for the young and perhaps also the
energetic demands (thermoregulation for example).
In the second model (equation S), it was assumed that GEI was a function of bodyweight.
In this model the major assumption was that sex and condition effects at the age of 24
days, are the same as age effects on the energy intake. In the higher age regions, where
no or negative growth occurs, GEI was overestimated. Krijgsveld measured a reduction in
GEI. Contradictory to a reduced energy demand due to reduced growth later in the
nestling period, energy allocation to growth is expected to be replaced by a higher DEE
(energy allocated towards training of flying musculature for example).
In the second part of model 2 (eq.6), it was assumed that DEE was a power function of
bodymass, which of reasons mentioned above, gave a wrong estimation at the beginning
and toward the end of the nestling period. Moreover, the energetic density of the tissue
varies with relative bodymass (Klaassen 1994) and was here treated as a constant.
There are several other costs during maturation that cannot be incorporated in the model,
such as thermoregulation, feather synthesis, heat increment of feeding etc.
Theory predicts that the sex ratio (on a population level) should be inversely proportionaI
to the ratio of the costs of rearing a male and a female (eq.7). The estimates obtained
from the GEI via the water-influx (0-36 days), were closer to the laboratory
measurements than the estimates of the E,method. All estimations of GEI over the total
period of parental care (0-70days) had a smaller ratio than the ratio found by Krijgsveld
(1994). This was either an artefact of the estimation methods or a result of postfledging
mortality. The ratio becoming smaller, females suffer higher postfledging mortality than
males.
5) Concluding remarks.
The data presented in this paper, have a small basis. GEI, is an indication of what the
energetic demands of the growing youngare. They can, however, only reflect the true
costs of parental investment. In both the laboratory and the field, the data are only
applicable for chicks that survive until fledging.
The sex ratio, to which Fishers theory is being tested at its merit, is not the true sex ratio
in the Fisherian sense. It is the sex ratio at fledging, not the sex ratio at the end of
parental care. Moreover, the energetic investment of parents in young that suffer
mortality, are not included in the costs of raising young.
It is likely that differential mortality is caused by differences in food requirements of the
sexes. The bigger part of mortality, however, occurs early in the nestling period. In this
period the differences in energetic demands between the young, are mainly caused by the
size differences due to asynchronous hatching. The chicks that hatch later in the sequence
are the most likely to suffer mortality. In the field, where chicks were individually
marked at an early age, it never occurred that a young, hatching earlier in the sequence of
laying, died before a chick that hatched later. The exception to this, was the mortality of
young before all chicks are hatched. This only happened in six, and seven clutches to
m n g 5 in the sequence of hatching. The young that hatched later in these cases, also
..~.fferedmortality. If differential mortality occurs in the Marsh Harrier, it probably is
highly correlated to the specific sequence over which, the sexes are distributed.
V. References
-Charnov. E.L. (1993) Life History invariants. oxford series in Ecology and Evolution.
-Glutton-Brock, T.H. (1986) Sex ratio variation in Birds. IBZS 128:317-329.
-Dijkstra er al. (1988) Reproductive tactics in the Kestrel Falco tinnunculus. A study in
evolutionary biology Diss.RUG
-Fisher, R.A. (1930) The Genetical Theory of Natural Selection. Clarendon Press, Oxford.
-Gesseman, J.A. & K.A. Nagy (1988) Energy metabolism: Errors in gas-exchange
conversion factors. PhysioLZool. 661 507-513.
-Glutz van Boltzheim, U.N., K.M. Bauer & E. Bezzel (1971) Handbuch der Vogel
Mitteleuropas, Band 4, Falconifomes. Akademische Verlagsgesellschaft Fran.@~.
-Kirkwood, J.K. (1983) A Limit to metabolizable energy intake in mammals and birds.
C o y . Biochern Physiol. 75A:l-3
-Klaasen, M (1992) The Naive proficient. Diss.RuG
-Krackow, S (1993) Note on the falconiforme sex ratios given in Olsen and Cockburn 1991:
Avian raptors exhibit no unique sex-ratio bias. Behavioral Ecology and Sociobiology
32:429-430.
Xrijgsveld, K . (1994) VI. Energie opname en groei van de Bmine kiekendief Circus
aeruginosus. Intern rapport rijkswaterstaat 1994 -39Lio.
-Lifson, N &R. McClintock (1966) Theory of use of turnover rates of body water for
measuring energy and material balance. J. Theor. Biol 12:46-47.
-Masman, D (1986). The annual cycle of the Kestrel. Diss.RuG
-Newton, I.(1973) Feeding and development of Sparrowhawk Accipiter nisus nestlings. J.
Zool. London 184:465-487.
-Olsen, P.D. & Cockburn, A. (1991) Female-biased sex allocation in Peregrine falcons and
other raptors. Behnvioral Ecology and Sociobiology 28,417-423.
-Richer, H. (1991) The growth and dynamics of sexually dimorphic birds and Fisher's sex
ratio theory: does sex-specific growth contribute to balanced sex ratios? Func.Eco1. 5: 19-28.
-Ricklefs R.E. (1974) Energetics of reproduction in Birds. In Avian energetics. Ed. by R.A.
Paynter Pybl. Club Mass..
-Ricklefs, R.E. & S.C. White (1981) Growtb and energetics of chicks of the Sooty tern
(Sternafurcara) and Common tern (S. hirundo). Auk 98:361-378.
-Trivers, R.L. & Willard, D.E. (1973) Nanual selection of parental ability to vary the sex
ratio of offspring. Science 179:190-192.
-Witkofski, J (1989). Breeding biology and ecology of the Marsh Harrier Circus aeruginosus
in the Barycz valley, Poland. Acza ornit. Vo125 no3:223-320
-Zijlstra, M., Daan, S. & Bruinenberg-Rinsma, J. (1992) Seasonal variation in the sex ratio
of marsh hamer Circus aeruginosus broods. Functio~lEcology 6,553-559.
VI. Appendices
Appendix 1.
Mean bodymass per age of males and females (figure 1): sd = standard deviation and n =
number of points. Data from Lauwersmeer 1990-1994 : selection of surviving young (see
text).
ma1 es
age
mean
0
30.0
sd
-
females
n
mean
sd
1
31.3
5.3
one way AOV
n
4
P
0.8437
Appendix 2.
Characteristics of nestlings used in DLW measurements:
NNR indiv Age Dl
39
39
18
18
25
8dd'Q
8889'
98'9
989'
993'9
25
24
25
23
24
165
165
165
165
166
T
,,,,,,
10:41
10:47
13:12
13:04
15:16
,,,,
T
12:12
12:34
14:40
14:45
17:06
,,,T
12:09
12:21
14:50
15:OO
17:45
Bh,
555
583
550
680
5 1
Bh2
-
-
540
637
582
700
582
-
H,O,.
DEE
8.28
10.82
7.66
8.18
8.26
439.3
635.9
820.9
863.0
549.7
%bodywater
77.06
79.30
76.09
79.88
76.20
I n d i v i d u a l s used f o r background measurements:
Legend.
The first column (NNR)represents the identification number of the nest. In the second
column broodsize, sex ratio and sequence are displayed of the chick injected with DLW
(7. The third column represents the age of the injected individual in days. D, is the date
T T,, and T
, is the time at which resp. the
the individual was injected (julian date). ,
individuals were injected, an initial bloodsample was taken on D, and a final blood
sample was taken two days later (hours:minutes). BM,, and BM, is the bodymass
(grams) of the individuals at resp. T ,and Tm,the sign after the rmmber indicates if the
crop of the individual was either empty (-) or filled (+). H,O, is the calculated amount of
water intake in moleslday and DEE is the calculated Daily energy expenditure (Wday).
The last column is the measured percentage bodywater, calculated without extrapolation.
The last four individuals were used as background samples (to measure natural isotope
ratio's ) and were not treated with DLW.
Appendix 3.
Data used for DLW calculations in D20l.exe as delivered by the 'Centrum voor Isotopen
ondenoek' .
NNR indiv
6lB0fina1
886'9
888P'
98.9
989'
996'9
99'89
98.88
9.888
86'96
889'6
98'989
9'8989
6'99
89'9
8'99
89'9
267.47
248.69
260.45
273.28
273.72
268.20
260.29
302.26
276.24
246.24
231.11
244.05
346.41
310.23
275.62
260.80
39
39
18
18
25
25
40
40
21
21
20
20
44
44
8
8
t
i
611.01
635.60
623.66
565.87
666.74
610.86
639.03
618.74
675.18
572.86
588.19
671.37
792.88
711.57
669.89
669.72
8'Hiinal
2048.4
1993.5
2198.1
2235.2
2196.5
2098.3
2061.1
2386.1
2243.4
2014.7
1867.2
2016.6
2803.2
2425.2
2199 - 8
2078.7
b2Hinitial
4038.4
4266.1
4099.0
3764.8
4462.2
4045.6
4241.0
4078.6
4486.0
3794.6
3925.0
4496.3
5155.3
4586.5
4515.8
4490.0
Background measurements:
Legend.
The first two columns identifies the individual (nestnumber and sequence of hatching,
injected individuals are marked (3).6180r,, and 6180- are numbers that specify the "0
contents of the final and initial blood sample taken after treatment whereas #Hr,, and
62Hm specify the 2Hcontent. All values are means of two samples analyzed in one
session differing no more than 2%. The backgrounds are used to estimate the natural
occurrence of 180and 'H.
The Isotope ratio of the injected DLW was: 11.7889 gram H i 8 0 (90.79AP), 5.7562 gram
'H20 (99.9 AP) .
The calculations were performed without the extrapolation of bodywaterpercentage to the
time of injection. RQ was assumed to be 0.72 and energetic equivalent of 1 litre oxygen
19.8 kJ (Gesseman & Nagy 1988).
I
!
Climatal conditions during the period of DLW measurements. The hews rrp~sentdata
m e d in Eelde. The X-axisindicates the date in julim days (ianuary I' = 1). The
horizontal black bars indicate the true measuring days.
1
I
\
*. v\
/-A+
A-A
.-T-.\,
V-V'
v'
-\
'/-k~-l
A
v\
'FAA p-"
dv
p-A-A
fkA>-kA
4~p
r(
I I
I \
f
--
tempe
-0-
humid
-0-
rain (I
- -
rain (
I
.-c
m
n
3
0
I
\
Appendix 5.
GEI calculated per individual by two different methods. The first uses the measured H20influx to estimate GEI (eq.2) and the second method (eq.3) assumes an energetic density
(Ed) of the tissue of 7k.I (Ricklefs 1973).
-
-
-
-
NNR indiv Age D l
39
39
18
18
25
25
40
40
21
21
20
20
44
44
8
8
866'9
8dd9'
96'9
969'
996'9
99'89
98'88
9'888
86'96
8 8 8
96'969
9'898?
8'99
89'9
6'99
89'9
25
24
25
23
24
25
25
25
24
23
24
24
25
24
24
23
165
165
165
165
166
166
167
167
168
168
173
173
186
186
188
188
DEE
GE1~2~influx
439.3
635.9
820.9
863.0
549.7
628.7
532.6
679.3
547.1
838.7
653.8
797.5
555.6
630.5
485.1
595.9
mean (sd) 8 8 : 1 2 1 6 . 6 k 1 6 2 . 6
99: 1 4 5 6 . 4 k 2 2 5 . 8
1261.4
1647.2
1165.9
1245.9
1257.4
1470.0
1313.8
1181.8
1139.7
1484.6
1454.8
1805.0
891.5
1216.6
1248.0
1600.0
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544.8
1164.3
1316.4
1314.0
1107.0
1119.6
811.8
944.5
598.0
1082.7
1327.5
1640.8
881.1
1040.8
794.2
1073.4
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+33.5
+23.5
+6.0
-1.0
-17.5
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+41.0
+52.5
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+15.5
+11.0
+23.5
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