ABSTRACT
For the purpose of this study, the term “wading bird” encompasses two orders of bird;
Ciconiiformes and Charadriiformes. Within the Neotropical region, avifauna is especially
rich (Stotz, 1996), containing around 3400 of the world's 10,000 bird species, 1500 of which
occur in the Amazon basin alone (Butler, 2006). Despite this rich diversity however,
relatively little is actually known about the wading birds in the region and they remain poorly
studied. The primary aim of this project was therefore to establish which species of wading
bird occur in the Pacaya- Samiria National Reserve, Peru, in order to provide baseline data
from which future comparisons can be made.
Aquatic birds in particular are one group of taxa that have been suggested to act as an
ecological indicator for the health of the ecosystem (Furness et al, 1993) which further
increases the significance of this study. Changes in hydrological processes and water quality
can directly influence bird behaviour which can act as early warning signals to indicate
changes within an ecosystem (Ormerod & Tyler, 1993). For less economically developed
countries, this early warning system can be crucial as alternative costly methods may not be
available due to the lack of money or expertise available.
A total of 210km of transects were completed over a period of 13 days for three set transect
types. During this period 135 individuals were seen across seven species of wading birds. Of
the seven species encountered, just three accounted for 86% of the total sightings. The most
abundant species was the Wattled Jacana, comprising 37% of all sightings despite being seen
99% of the time in just one transect type. This was followed in abundance by the Cocoi
Heron and the Capped Heron, comprising of 31% and 18% of all sightings respectively. In
terms of habitat importance, the upriver habitat was the most species rich but the lake habitat
had the highest abundance of individuals.
During this study the sampling method was also analysed which highlighted a number of
biases and ways in which the methodology could be reformed. Furthermore, river levels
dropped by 42 centimeters which allowed for comparisons to be made between water depth
and bird abundance. It was expected that more birds would be seen as the number of
available habitats increased as banks on the river become exposed. However, this was not the
case due to unusually high water levels encountered throughout the period which were the
highest seen in years, if not decades (Bodmer, 2009). This meant that although the water was
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dropping throughout the study period, it did not drop to a level which caused any significant
changes in the habitats for wading birds. This may therefore have resulted in an
underestimation of the birds that occupy the area as birds that would normally occur during
the low water period were not encountered.
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LIST OF FIGURES
Figure 2.1
River transect within the study area………………………………………
Figure 2.2
Map of Pacaya- Samiria National Reserve……………………………….. 5
Figure 2.3
Map of the study area, Rio Samiria ………………………………………
6
Figure 4.1
Species presence and abundance …………………………………………
12
Figure 4.2
Habitat abundance and species richness…………………………………..
13
Figure 4.3
Average number of birds per transect between the start and end period…. 16
Figure 4.4
Trends in the number of Wattled Jacana over the Study Period………
17
Figure 4.5
Bird species averages for morning versus afternoon transects…………..
18
Figure 4.6
Motor on versus Motor off………………………………………………
20
Figure 4.7
Differences in bird abundance between the way up and the way back of
transects………………………………………………………………….
21
Comparisons between wading birds seen in 2004 and 2009…………….
22
Figure 4.8
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4
LIST OF TABLES
Table 3.1
Study Site Locations………………………………………………
8
Table 4.2
Species presence and abundance………………………………....
11
Table 4.3
Habitat abundance and the average number of birds per 5km
transect……………………………………………………………
12
Table 4.4
ANOVA to test for a significant difference between the mean
abundance for the three habitats………………………………….. 13
Table 4.5
Comparisons of Margalef’s and Menhinick’s indices across three
habitats………………………………..…………………………..
14
Table 4.6
Comparisons of the Shannon-Weiner and Simpson’s diversity
indices…………………………………………………………….. 15
Table 4.7
Chi Squared test between the number of birds observed in the
morning and afternoon compared to the number of birds
expected…………………………………………………………..
Table 4.8
19
ANOVA between the ‘Way up’ and the ‘Way back’…………….. 21
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