Birdwatching is all about time and place and there was no better place to be for a group of international students than the banks of the Sandy Bay Rivulet earlier this month.
By chance, the students had arrived for a community conservation initiative just as the first birds of spring were arriving from the mainland.
It made the talk I was giving on the wonders of birds so much easier to deliver. All I had to do was concentrate on the wonders of bird migration.
As part of the University of Tasmania’s community service program, the students regularly assist the Friends of the Sandy Bay Rivulet weed and plant trees and the day’s activity always starts with a talk on the flora and fauna of the water course.
Migratory birds proved a fascinating subject, especially as the first of the migrants travelling from beyond Bass Strait, fan-tailed cuckoos and striated pardalotes, were singing from nearby trees.
As I explained to the students, birds navigate by using the position of the sun, the stars, the Earth’s magnetic field and also physical landmarks like hills, mountains and rivers. They can also transform their bodies in readiness for the epic journeys, some doubling their weight to provide “fuel” for long-distance flight.
A student from Nepal was interested to hear of the bar-headed goose, which reaches altitudes of more than eight kilometres when flying across the Himalayas on its annual migration from central to southern Asia.
And a student from Denmark wanted to learn more about a long-distance traveller, the northern wheatear, which visits her home. The wheatear travels up to 14,500 kilometres on one of the longest flights of any songbird, to its breeding grounds in northern Europe from Africa. This is an amazing feat of endurance considering the tiny bird weighs about 25 grams.
When it comes to long-distance migration, nothing compares with the Arctic tern. These seabirds fly about 30,000 kilometres a year, making a round trip between their breeding grounds in the Arctic and Antarctica. The lucky bird gets to see two summers a year.
Although the students were most likely to see and hear woodland and forest migrants in Hobart, out on the local mudflats is a species that ranks in the Audubon Society of America’s Top Ten of remarkable migrants. This is a large shorebird, the bar-tailed godwit, which holds the record for the longest non-stop flight – a staggering distance of just over 13,035. The godwit flies along the East Asian-Australasian Flyway to and from breeding grounds in Siberia and Alaska, to Australia and New Zealand.
In times gone by bar-tailed godwits could be seen probing the mud where the rivulet meets the Derwent in Sandy Bay. Disturbance has put the shy godwits to flight at this site but they can still be seen on the wetlands of Sorell and Lauderdale.