Melbourne Shorebird Floating Roost Update
The three floating roosts at the Werribee Treatment plant have now been in place for two weeks and colonisation has begun! Both above and below the water. Given the varying conditions and localised waterbird populations we’ve seen some early differences between the 3 sites – the trend-setters, the invertebrate response and how birds use the roosts.
T-Section Pond 6 (non-tidal, freshwater pond)
Chestnut Teal were the early adopters. With a solitary bird observed on day 2, we now regularly observe up to 20 birds. Whiskered Tern feed around the bag field perhaps taking advantage of localised eddies of water which concentrate invertebrates in the water column*, and roosting in small numbers. Algae has begun to coat the shells and bags providing a novel food source for our first shorebird visitors, Sharp-tailed Sandpiper.
*CEE consultants will look at invertebrate distributions as part of our parallel study into the ecological effect of the trial.
The Spit NCR (sheltered tidal lagoon)
Although not as popular (yet) high-tide brings in a small list of regulars including Common Greenshank and Sharp-tailed Sandpipers which are using the site for both roosting and to continue feed throughout the tide cycle. Although the sediment in this basin at the northern spit is extremely soft, the water (when undisturbed) is crystal clear and small fish have been observed sheltering in the bag field.
Little River south (intertidal)
The sea has been rough my friends. This roost has copped a battering, but has withstood. At first merely a curiosity to most, the only use this roost seemed to serve was to concentrate invertebrates on the windward side for opportunistic Avocets perusing the aisles and feeding in the water column. Then in the heat of the day, two hours before high tide, a single Whiskered Tern became an influencer. Compatriots leaving nearby beaches and sand spits would hover over the tern calling. Initially, some would land but more would move on. However, as the water began to rise more and more would return often visibly hot, mouths agape and land, wetting their feet and settling in. Before long over 150 individuals including Crested Tern, Whiskered Tern, Silver Gull and Red-necked Stint were roosting on the bags bobbing in the bay and attracting attention from curious patrols of Pelicans.
The observations above have been made on my few visits to the sites over the last couple of weeks or via the one remote Arlo camera installed at T-section. They are fleeting and I no doubt miss a lot as the trials or only targeted at providing temporary, supplementary roosting during high tide. While we hope to install cameras at each site and have the capability to stream this footage live through the mobile network, resolution is not very high.
This is where you can help out!
Datasheets (found here) have been placed at all three roost sites (map here). If observers would like to contribute data they can do so using the following method:
Standing at or near to the accompanying sign count all birds observed on the roost in a 10 minute period. Note species, position, and count (by bag), as on datasheet.
The floating roosts are designed to provide supplementary high-tide roosting opportunities, so surveys should ideally be conduct at or close to high tide. Opportunistic surveys outside this window are also welcome (including 0 counts!).
If you revisit the same site more than once in the same tide cycle multiple 10 minute surveys can be submitted.
Temperature and wind conditions are useful variables in identifying why the roost may or may not be used at the time of surveying. Please provide your best indication. Your phone’s weather report for Pt Wilson will do.
Submitting your data
Data will be entered manually so if you are not submitting a Floating Roast Trial datasheet please try and record the fields in a consistent with those outlined above.
Snap: email a photo of your notebook
Print and Scan: print the datasheet, fill it in, scan it and email it back.
Post: send your datasheets (on bulk or singles) to Post: send your datasheets (on bulk or singles) to Chris Purnell, Birdlife Australia, Suite 2-05, 60 Leicester Street, Carlton VIC 3053.
You may notice a few tags on the bags or attached via red screw anchors at nearby natural roosts, these are project thermologgers (contained within black pill boxes). Charged with the task of monitoring the temperature at the roosts they’ll hopefully give us an insight into roost selection/preference. Please let me know if you see any go wayward.
Please don’t hesitate to get in touch with queries comments and feedback.
Thanks again to Melbourne Water and Parks Vic for continued support.
Cheers for now,
Chris Purnell | Wetland Birds Program Manager