Birdbath use in Karori Wildlife Sanctuary
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Alysia Barnes
Travis Chelman
Tim Markwell, Ph.D. (Supervisor),
School of Biological Sciences, Victoria University of Wellington
Example of a post-mounted bird bath.
On offshore island bird sanctuaries (e.g. TiriTiri Matangi) birds congregate at birdbaths. If these baths are correctly located, birds will “queue up” waiting their turn at the bath. This indicates the importance of water as a resource to the birds over the summer months. Bathing birds, even relatively common species such as silvereyes (Zosterops lateralis), provide a focus for visitors, and facilitate observation of the birds at closer range than might be possible if the birds remained in the forest canopy. However, the location of baths may influence their use by birds. In order to enhance the experience of visitors to the Sanctuary, and provide a resource for birds over the summer months, we installed bird baths at different locations around the sanctuary and recorded their use by birds over summer 2003/2004.
Another example of a post-mounted bird bath.
Birdbaths were constructed from plastic plant-pot bases mounted on posts or fixed to the ground. A second pot was nested inside the first, which allowed easy cleaning and removal of fallen leaves etc. Baths were placed at Tui Terrace and along the Round the Lake Track. Two North Island robins (Petroica australis longipes) were recorded bathing in ground baths. Feathers and faeces were found in several post-mounted baths, suggesting their use despite lack of sightings.
With low bird sightings, baths were moved away from reservoirs and streams into drier areas such as on the Tui Glen Track and Turbine Track. In the second bath placements we observed a total of eight robins using ground baths at five different sites.
Ground-fixed bird bath
Six tui (Prosthemaderma novaeseelandiae) were observed using the post baths at three separate sites. Silvereyes were observed at only one site, at which 10 were observed drinking from the ground bath and one was observed drinking from the post bath. In the second round of sites, feathers were only found in baths where birds had been sighted. No clear pattern of preferential use of shaded vs. exposed baths was noted; however all baths used had some degree of canopy cover.
Although we saw several robins using baths, we noticed that a large proportion of them were only drawn to the baths because we were near by. This makes it difficult to conclude whether we would have had as many robin sightings if we were not there. This study was conducted over the summer, when water is most likely to be limiting. However, summer 2003/04 was particularly wet, with February rainfall six times higher than average. This very high rainfall may have reduced the importance of water as a limiting factor and minimised the number of birds using the baths.
Our results suggest that, to encourage a range of species, baths should be provided at both ground level and mounted higher up. Although alternative designs were not investigated, the baths used were effective and economical. The presence of a distinct ledge allowed birds to perch at the edge while drinking. It is possible that other bath designs (such as incorporating a sloping ramp) may also be effective. The study showed that location was important: sites with canopy cover, further away from other water sources were most attractive to birds.
Overall, ground and post-mounted baths are likely to be used by Sanctuary birds, and will potentially make birds more visible to visitors to the Sanctuary. However baths should be placed in areas with at least some canopy cover, and their use will be greater at times when alternative water sources are scarce.
Profile
Travis Chelman & Alysia Barnes
Alysia and Travis carried out this work as part of a summer research project in the Sanctuary.
Travis is a native Californian who will graduate with a BSc. in Ecology and Biodiversity from VUW in 2005. He is currently in California completing the final courses for his Vic degree at UC Santa Cruz. His interests include orchid, fungi and fern ecology.
Alysia is a New Zealander. She will graduate B.Sc. in Ecology and Biodiversity and BCA in economics in 2005, and is currently in Wellington working on her final-year papers for both degrees.
Published July 15, 2004
Updated Oct 8, 2004