Penguins on St Kilda Breakwater
By Zoe Hogg . Copyright Earthcare St Kilda
 
  The object of this report is to summarise observations made on the Little Penguins inhabiting St Kilda Breakwater, with particular reference to
   
 

·Number and Distribution of penguin sightings since reconstruction of the St Kilda Breakwater, completed in June 1998
· Number and Distribution of Breeding sites since reconstruction.
· Estimates of penguin population since 1998
  Reconstruction of the breakwater over 4 years ending June 1998, was confined to the months of May and June each year, in order to minimize disruption to the breeding cycle of the Little Penguin Eudiptula minor community.

   
  Earthcare St Kilda gradually revegetated the breakwater during these four years and in subsequent years to the present day. Plants used were; Atriplex cinerea Coast Saltbush, Atriplex paludosa Marsh Saltbush, Carpobrotus rossii Angled Pig Face, Disphyma crassifolium Rounded Noon Flower, Frankenia pauciflora, Southern Sea-Heath, Halosarcia halocnemoides Shrubby Gasswort, Poa poiformis Coastal Spear Grass, Tetragonia tetragonioides New Zealand Spinach, Sarcocornia quinqueflora Beaded Glass Wort and Suaeda australis Austral Seablite.
   
  The cover provided by this vegetation created more, safe breeding sites and caused the penguins to colonise sites along the whole length of the breakwater, in contrast to the previous dispersed pattern of burrows. Despite this they still remained in large quantities at easy landing sites that have little or no cover and completely stayed away from sites that were steep and had no vegetation. A few penguins took up residence on the seaward side of the breakwater and have remained in these sites for the last 6 years, but these sites are accessed from the landward side. Penguins have rarely been seen coming ashore on the seaward side since the start of systematic observation in 1986, although one recent observation on the seaward side in 2004 recorded several birds coming ashore within 50m of the pier. The most recent self-seeded Atriplex cinerea bush at the kiosk end of the breakwater attracted two sets of penguins during 2004 and one pair reared two chicks.
   
  The Breakwater is marked every 10metres and has an alphabet marker every
20 metres.(see Fig.1). Lower case letters are used from the kiosk to the gate and upper case from the gate to the end. At Letters O, P and Q, penguins find easy access from the bays on each side of the corner and from the small pebble beaches supplied during construction of the breakwater. At letter R some flat preening rocks were placed and these attract many penguins. Letter U at the very end is an obvious first landfall for the raft of penguins that collects near Kerferd road pier. Letters E and F are on the Eastern sheltered side of the turnaround on the breakwater and at letter C there are several Atriplex cinerea bushes. The Yacht Squadron Judge's box at letter c is a clear favourite probably providing shelter from SW winds. Letters g and h are at the Western end of the board walk and have Atriplex cinerea bushes, letter j has access from a small beach and has Atriplex cinerea. The area from l to a is open to the general public.
The increased vegetation has had a marked effect on the choice of burrow location with many more penguins choosing to live among the Atriplex cinerea bushes.
Figures 2 to 6 show the location of breeding sites, number of sightings of penguins and location of Atriplex cinerea bushes.

 
  Breeding sometimes begins in June hence the St Kilda Penguin Study Group uses the format May through to April as the penguin year.
The data used in this report begins in June 1998 after the reconstruction of the breakwater but subsequent years begins in May and ends in April through to 2004
   
  It was the policy of the group not to band penguins from January 2002 to October 2002, hence there are records of unbanded adults (uba) during that period which cannot be sorted into individual penguins. In November 2001, 13 penguins were microchipped as a trial. From October 2002 all newly caught penguins have been microchipped.

   
  The Little penguin population has been steadily growing during these 6 years with a large recruitment during the 2003/4 season. The population number is calculated from the number of breeding sites per season and assumes that 43.1% of the population breed each year.1
   
 
Year
No.breeding sites
Population estimate
Total no. penguins handled
No. individual penguins handled
1998/99
71
346
224
107
1999/00
67
310
237
138
2000/01
95
441
373
182
2001/02
93
432
297
133 +62 uba
2002/03
92
427
316
205 (83 bands, 122 chips)+48 uba
2003/04
112
520
492
322(71 bands, 251 chips)
  Penguin breeding sites correlate closely with the distribution of penguins at any time on the breakwater. Many penguins stay around the same site all their recorded life.
Summary
The population has increased since 1986 but there will always be uncertainties about numbers due to the structure of the breakwater.



fig 2
   
  Fig 3
   
 
   
 
   
Acknowledgements I would like to thank to all those volunteers who participated in the collection of data, and to Neil Blake for his continued support.
  2 Cullen J.M. (Dept. of Botany & Zoology, Monash University). St Kilda Penguins 1989
Cullen J.M.Blake N. Data of the St Kilda Penguin Study Group 1986-2001 p150-151
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