St Kilda Penguin Colony
Report 2009-10
Zoe Hogg
The penguin monitoring team only missed one session this year due to bad weather and we always had a good
number of volunteers on monitoring nights.
The penguins were lighter than usual during this season but they maintained a very steady average weight and
evidence of breeding was recorded at 262 sites.
There are three teams monitoring the breakwater each with a similar distance to check.
In area one ( close to the kiosk) there were 111 breeding sites, area two, 87 breeding sites and area three, 63
breeding sites. Area three is being extended to provide shelter for yachts this may also give a good sheltered
area for penguins to land and we may see the breeding patterns change over the next two seasons.
The estimated population for 2009-10 is 1215. The last time the population was around this number was in
2005-6 when the average weights were also lower. (see graph below) In that year we microchipped 250
penguins and this year we microchipped 248 penguins.
Season
2009-10
2008-9
2007-8
2006-7
2005-6
2004-5
2003-4
Number
breeding sites
262
170
184
177
221
146
112
Number
individual
adults caught
574
451
485
508
555
465
320
Total number
of adults
caught
986
786
845
833
880
684
426
Adults seen
but not caught
Population
estimate
1323
1927
1864
1662
1846
1788
1123
1215
789
854
821
1025
677
520
Number of newly microchipped Penguins
Year
Male
Female
2009-10
2008-9
2007-8
2006-7
2005-6
2004-5
2003-4
62
31
39
48
62
61
62
99
43
60
50
96
93
111
Not sure of
sex
9
5
4
3
14
12
12
Chicks
Total
78
51
43
42
52
26
32
248
130
146
143
224
192
217
Over the last three years our performance has improved for catching and microchipping chicks.
2007-8 11.4% chicks with ID, 2008-9 17.05% chicks with ID, 2009-10 27.5% chicks with ID.
The number of newly microchipped females compared to males this season suggests that many of them were
immature adults and were chicks from the previous season that we failed to give an ID.
The feather analysis for toxins is underway and we hope to publish the results soon.
There is also some blood sampling for toxic analysis in progress.
Due to the extension of the penguin guide program where penguins have been watched every evening for six
months, we have had some reports of penguin behavior we have never seen before. Some of these behaviors
will be described in future Earthcare newsletters.
The penguin guides also rescued and reported many instances of penguins caught in fishing line, ring pulls,
plastic bags and other rubbish. This suggests that we actually lose more penguins to rubbish entanglement than
previously thought.
We are still catching some penguins originally banded in 1993 and many other banded penguins from 1994 to
2000 who are not caught easily. We can only remove their bands when they come in to moult and are much
quieter.
Some penguins around letters D, L, J, K and M have been caught as many as 11 times this season. Is this
because their burrows are less deep and the penguins easier to catch or are they becoming less frightened of
humans?
I feel this is something we should investigate as this colony should be kept as wild as possible.
The intrepid pair of penguins on the outer seawall at letter N finally raised one chick on their third attempt. They
were completely washed out twice during storms but they kept trying. They originally arrived on the breakwater
in 2004 and were back in their burrow during April. They are both very feisty and this is one pair we will never
catch 11 times in a season.
Average male and female weights 2008-9 and 2009-10
1500
male 09/10
female 09/10
weight in grams
1400
male8/9
female 8/9
1300
1200
1100
1000
may
jun
jul
aug
sep
oct
nov
dec
jan
feb
mar
apr
Average male and female weights 2009-10 and 2005-6
male 09/10
1500
female 09/10
weight in grams
1400
male05/06
female05/06
1300
1200
1100
1000
may
jun
jul
aug
sep
oct
nov
dec
jan
feb
mar
apr