28 February 2021
Author: Liz Downes, Vice President, Wildlife Queensland Townsville Branch
For the 56th successive year (yes, you read that correctly) a series of pied imperial-pigeon counts at North Brook Island was completed in February 2021. Long supported by the Cassowary Coast & Hinchinbrook and Townsville Branches, and funded by Queensland Parks and Wildlife Service and the Thorsborne Trust, four trips were made between October 2020 and February 2021. Marine Parks and Girringun Rangers joined Wildlife Queensland members and community volunteers, with Judy Murphy (Cassowary Coast Branch) as co-ordinator. Zoologist Dr John Winter, who has participated, analysed and championed these counts since the 1970s, was our respected guide and mentor.
There is always a sense of anticipation as we head out across Rockingham Bay, with the bulk of Hinchinbrook to starboard, Goold Island to port, and ahead, the small humps of the Brook Islands, 30km off the coast. The count begins at 3.30 pm when the birds start returning from the mainland forests, but first, there is other work to do. We patrol the beaches for litter washed up with the tides; we watch for and record nesting sites of black-naped terns or beach stone-curlews, carefully avoiding disturbance; we record changes in vegetation or dune structure and observations of other birds or marine life. Turtles, rays and black-tipped reef sharks are commonly seen. On February’s trip, unmistakeable tracks leading down the beach suggested a turtle (Hawksbill?) had chosen North Brook for her nesting site.
The boat’s canopy provides welcome shade as we get down to business. Two teams, consisting of one counter and one scribe, are required to cover the northern and southern approaches to the island. In the early stages, new counters can practice their skills but, as larger numbers flood in, more experienced counters are called on. Counters need the ability to see flocks close-up, in the middle distance and on the horizon; scribes need intense concentration to record the counter’s rapid calls, so tired eyes and cramped fingers need periodic relief. Additional counters may be required to call the outflying birds, those which have remained at the nest all day and take the chance for a quick feed when their partner returns. Replica counts are conducted to obtain an indication of between-counter variation.
As the light fades the furious pace gradually slows and there is time to take in the beauty of the sea-scape and of the birds themselves. When it is too dark to see clearly we set off under a full moon towards the lights of Cardwell.
Prior to Cyclone Yasi’s devastation of coastal and island forests in 2011, the peak counts were averaging around 33,500 birds. Since then, despite an initial strong bounce back, the numbers seem to have plateaued around 22,500. Despite a strong start in October with 17,955 birds, this season’s December total was 21,459. While there is uncertainty about why the pre-Yasi numbers have so far been unattainable, there is no doubt about the need for northern Wildlife Queensland Branches to stay involved with these counts and help to steer them, and this important breeding colony, into a secure future.