REPORT ON STAGE 4 ST KILDA BREAKWATER RECONSTRUCTION IMPACT ON LITTLE PENGUIN COLONY

Neil Blake

Port Phillip Ecocentre

Ph. 03 95340413 Email. coord@ecocentre.com

1. Introduction

Parks Victoria commissioned the author to work with the construction contractor for 3 hours each morning for the duration of Stage 4 works which commenced May 15, 1998. Two roles were specified in relation to the works

(a). To conduct daily pre-works searches to remove penguins from the works area and liaise with the contractor (Marty Stankard) and Parks Victoria Ranger (Ian Ellis) in relation to construction around sensitive sites.

(b). To monitor and report on the impact of the works on the Little Penguin colony.

This report describes the measures adopted to fulfil these requirements, comments on the information gathered, analyses the current situation in the context of data collected by the St Kilda Penguin Study (StKPS), and documents aspects of the reconstruction which are relevant to impact on penguins and their habitat.

Special thanks are expressed to Professor Mike Cullen for his unstinting coordination of the StKPS since 1986, and for allowing the use of data collected over that time. Thanks also go to my fellow members of StKPS: Zoe Hogg, Linda McKenzie, Alison Oberg, Angela Suter, John Munro and Paul Bowler for their voluntary commitment (in all sorts of weather) to this essential task.

2. Data collection methods

Daily observations of penguin activity on the breakwater and at sea were collected in the morning generally between 6.45 - 8am and in the evening between 5.45 - 7pm. To minimise disturbance to the birds none were handled unless necessary to remove them from the daily works area. On these occasions band numbers were recorded.

With the exception of the StKPS visits, all evening observations were conducted without torchlight or handling birds. Night observations were made with binoculars from a fixed vantage point. Initial observations from ‘the Bend’ confirmed that birds were returning to that area. Subsequently, a second vantage point was adopted c30 metres from the outer end of the wall. This position afforded a good view of the new ‘beach’. Field notes were taken on location and movement of birds and their interaction with tour boats, newly constructed areas, and previously constructed areas.

3. Background to Stage 4

The reconstruction of the breakwater has been discussed and overseen by the Cooperative Management Area Committee since 1994. The decision to stage the works over several years and involve the same construction contractor throughout has helped to establish a working relationship where the requirements of all parties (including the penguins) were understood and respected.

Existing breeding sites (identified by StKPS during the 1997-98 season) in or immediately adjacent to Stage 4 area were mapped and this information provided to Parks Victoria project managers prior to Stage 4 work commencing.

4. Stage 4 strategies to mimimise impact of reconstruction

4.1. On-site Ranger presence

Parks Victoria Ranger Ian Ellis was on-site for the duration of the works. Ian’s involvement again proved invaluable in assisting with the morning searches, ensuring site safety for visitors, providing support for the construction contractor, and contributing his expertise to the placement of rocks to ensure structural integrity and minimise impact on the penguins.

4.2. Daily pre-works searches

The area to be worked on any given day was searched for penguins before construction work commenced. To assist searches the machine was used to open sites where birds found were otherwise unreachable, or where it was impossible to confirm that birds were not present and the site could not be built over without destroying it. Over the course of the works penguins were found and removed from the works area on 15 occasions.

4.3. Construction over & around breeding sites where possible

The construction contractor took particular care in the placement of rock so as to not disturb known breeding sites. This approach also extended to ensuring known penguin pathways from the water to the top of the wall were not eliminated. Marty Stankard displayed extraordinary skill in this undertaking.

This treatment was not appropriate for 2 sites on the path as their retention (essentially as holes in the path) would have compromised the integrity of the new structure.

4.4. Other measures to minimise impact and maximise habitat

4.4.1. Addition of Soil

60m3 of soil medium (a compost blend of recycled sandy soil and chipped green waste) has been placed along the inner shoulder of the wall in Stage 4. This material was supplied by Green Circle Environmental Pty Ltd and is similar to the soil donated by that company in Stage 3. Placement along the inner shoulder allows the soil to filter down into the spaces between rocks creating suitable sites for nests. This type of substrate has proved to be readily colonised by appropriate vegetation such as Rounded noon-flower (Disphyma crassifolium) which is thriving in these conditions. D. crassifolium is acknowledged as a plant species to combat erosion and Penguin Study Group has observed this plant commonly used by penguins for nest material.

4.4.2. Installation of ‘Stone Beaches’

In Stage 4 two ‘stone beaches’ around 2 metres wide and extending from just above the high tide line were installed (see map). One is approximately 15m long and the other 6m. These diversify the structure increasing the range of approach to the wall available to the penguins. Penguins have been observed using both beaches, sometimes pausing there before advancing up the wall. These structures will also enhance boat-tour viewing of the birds.

5. Monitoring the impact of reconstruction

5.1. Daily post works observations

Evening watches to observe the behaviour of birds returning from sea to the works area were undertaken on most works days. These watches generally commenced around 5.45pm and concluded when penguin contact calls at sea diminished (usually no later than 7pm). A watch position at ‘the Bend’ was initially used as this provided a view of the entire works areas and, importantly, of the area to be worked the following day.

Benefits of these watches include

· early observations in the works period showed penguins were attracted by the presence of large flat rocks, possibly because they provide safe rest areas for birds climbing up the wall (such rocks were thereafter incorporated where possible, particularly near existing neat sites);

· providing feedback to Marty and Ian on the results of the previous days work (particularly in relation to sensitive areas);

· providing an evening presence on the breakwater which signalled to the tour-boat operator and his patrons that every effort was being made to minimise the impact of the works on the colony.

· data collection on penguin movements at sea and on the breakwater, and on tour boat operations which are relevant to preparation of a Visitor Strategy for the breakwater.

5.2. St Kilda Penguin Study (StKPS) records

StKPS continues fortnightly monitoring of the colony. The visit on May 10 (preceding the works) recorded an unseasonally high 40 birds. 32 birds were found on May 24. 13 birds were found on June 7, and 31 on June 21. While May/June is acknowledged as the time of least penguin presence such variation is not exceptional.

5.3. Birds recorded in works area during works period

Band numbers and the locations where birds were found in the works area were recorded prior to the birds being released to sea (see Appendix 1). This information will be included in the St KPS data-base for future reference.

Throughout the works period an unusually early nesting pair of penguins were observed incubating eggs in a nest site concealed below a rock on the (Stage 3) shoulder of the wall. Incubation continued throughout the works despite the fact that up to 50 vehicle movements per day occurred within a metre of the sitting birds.

A penguin found dead at 7am on May 19 on toe rock about 1 metre east of the new works area and above high waterline was taken to Melbourne Veterinary Clinic for post mortem. It was found that the bird had a fractured skull. The source of the fatal blow remains a mystery although there are grounds to believe it was not related to the reconstruction.

· the Veterinary pathologist has advised that the injury was so severe that the bird would have either died instantly of at least been totally immobilised;

· a sparse and erratic trail of blood droplets leading from the path to where the bird was found suggested that the bird had been killed on the path and either carried or thrown down the wall.

A bird found moulting in the works area and was taken to Murrumbeena Wildlife Shelter was returned to the wall after completion of moult.

5.4. Confounding factors

Conclusions on the project success in terms of birds returning to the breakwater post-construction are confounded by

· the unpredictability of study visits coinciding with penguins returning from sea (possibly influenced by phases of the moon with greater numbers returning on the new moon than on the full moon, or by food availability);

· sites which have been built over are now inaccessible to the Study Group and therefore birds may be present but go unrecorded;

· birds recorded on the surface of the wall post-works may simply be investigating the new structure and their ultimate response will be confirmed by breeding activity or the lack thereof (this is made more difficult to establish because of the above mentioned inaccessibility factor).

6. Conclusions

6.1. Analysis of StKPS records in relation to reconstruction

StKPS records show penguins are fewer on the breakwater now than in 1994 (the year prior to Stage 1 reconstruction). In the year 1994-95 there were 194 different individual birds recorded compared to 103 in the year 1997-98.

Table 1 showing population trends since January 1987 sheds no light on the impact of reconstruction on the colony. Although figures up to 1994 steadily increase any comparison of this trend with figures for the reconstruction years must be considered in the context of the extraordinary 1995 ‘pilchard crash’. In 1995 records of penguins ashore for May to September hit an all time low following the pilchard population crash in May.

The dramatic decline in the penguin population which occurred in May 1995 is considered to have been triggered by the pilchard population crash, and not by reconstruction, for the following reasons

· the experience of Stages 3 & 4 has shown that penguins (including incubating pairs) apparently have a high tolerance of heavy equipment working nearby;

· penguin numbers ashore at St Kilda declined more than 30% in the 12 months following May 95 although reconstruction Stage 1 only affected 2 penguin sites (one where the male bird was known to have died prior to works);

· penguin numbers at Phillip Island suffered a similar catastrophic decline at exactly the same time as at St Kilda.

Following an apparent recovery from the initial ‘pilchard crash’ penguin numbers at St Kilda again declined in 1997. As this ‘second decline’ appears to have begun in March 1997 it can not reasonably be attributed to Stage 2 reconstruction. There is no evidence of the ‘second decline’ being exacerbated by Stage 3 and 4 of reconstruction. This decline was possibly the effect of an adjustment in the Bay foodweb triggered by exceptionally high numbers of barracouta in Port Phillip Bay over the year following the pilchard crash. Penguins are particularly vulnerable if food shortages occur in March following substantial loss of weight and condition during their seasonal moult.

The fact that the figures for the first half of 1998 are similar to the corresponding period of 1997 suggests that the colony has stabilised. Although the average of 18 birds per visit for the first half of 1998 is lower than the yearly averages this is not necessarily cause for alarm. In all years of the study the average number of birds per visit has been substantially greater in the second half of the year.

TABLE 1. StKPS records: average number of birds recorded per visit

	87	88	89	90	91	92	93	94	95	96	97	98
Jan	11.	18	19	16	20	17	30	40.	40.	13	16	16
Feb	16	16.	14.	21	22	20	42	41	65	12	20	10
Mar	13	16.	13.	26	17.	27.	39	16.	35	28	11	20
Apr	20	19	18	32	39	22	31	37	46	41	20	21
May	17.	18.	27.	24	21	27	30	47	10*	40*	23*	32.*
June	18.	14	17	28	27	26	45	53	7*	42*	19.*	21*
July	28	14	15	22	28	32.	19	29.	0.	30.	22
Aug	21	11.	20	31.	31.	36.	41	42	2.	30	25
Sept	20.	31	23	26.	34.	46	31	43	9.	34	29
Oct	25.	22	21.	33.	29.	55	53	55	35