I spent the last week catching migratory shorebirds with members from the Australasian Wader Studies Group (http://www.awsg.org.au/) and several hardworking Darwin locals. Our aim was to catch as many shorebird species and individuals as possible to mark them for my PhD study on migratory shorebird movement and habitat use in Darwin Harbour. These shorebirds breed in the northern hemisphere in places like Siberia, Alaska, Mongolia and China and then travel through the Yellow Sea region before reaching Australian shores for the summer season. Once they are in Darwin and other coastlines they spend their time roosting on beaches at high tide and then feed as the tide recedes. The birds feed on invertebrates on the wet sand surface.
We caught shorebirds at Lee Point and Sandy Creek in northern Darwin and in Darwin Harbour at the port site, East Arm Wharf. Lee Point is a place of international importance for some of these shorebird species and is therefore classed as a no dog zone. This is important as disturbances by dogs and humans walking along the beach can impact their energy stores for their migration and survival.
Each day we set cannon nets and then the next morning at high tide when the birds were roosting, we got into position and watched the birds until they were safely in the catching area. When we got the message “3, 2, 1 FIRE” over the radio from Dr Clive Minton (the shorebird ‘godfather’), it was time to run to the nets and extract birds. We had a very successful week with a total of 560 shorebirds caught from 12 species.
Each shorebird had a metal band applied to its leg and then coloured flags to the other legs. The yellow over blue colour combination represents that the bird was caught in Darwin and when these birds move around Australia or on their international migration they can be recognised by other shorebird researchers and this information is sent back to me for inclusion in my movement database. As well as these flags, the birds were measured and aged using their stage of wing moult. This can give us an indirect indication of their breeding success in the Arctic and tell us about body condition on arrival in northern Australia. Select individuals and species had radio tags applied to their backs so they could be tracked locally around Darwin to look at site connectivity and habitat use to determine site importance. The movement of birds around Darwin Harbour will help me inform management about which habitat and sites should be protected and will also give an indication about the quality of habitat.