A new study on one of the largest birds in the world, the wandering albatross, has shown that the birds have begun to breed earlier in the season.
In the study, done by a group of British researchers, it was found that, on average, the birds are laying their eggs 2.2 days earlier than in the past 30 years.
The reasons for this are unclear.
“Our results are surprising. Every year we can determine when the birds return to the island after migration, and the exact day they lay their eggs. We knew that some birds were laying earlier — those who were older or had recently changed partner — but now we see that those which haven’t bred successfully in the past are also laying earlier, and these birds are effectively driving this trend in earlier laying,” the lead author, Dr Sue Lewis of the University of Edinburgh’s School of Biological Sciences, is quoted as saying.
The research was done by using data from 30 years of surveys on Bird Island (part of South Georgia), located near the British Antarctic Surveys research station. Everyday, nest sites were monitored, during the laying, hatching, and fledgling periods.
Albatross numbers have been steadily declining on South Georgia, mostly from swallowing the hooks on fishing longlines and drowning. The number of birds on the island has declined by 50% since the 1960’s, down to the 800 breeding pairs currently alive.
“This work is important for understanding more about the behaviour of these charismatic and threatened birds,” co-author Dr Richards Philips of the British Antarctic Survey said. “In the Indian Ocean, an increase in the intensity of westerly winds has resulted in a shift in feeding distribution of wandering albatrosses. It is possible that earlier breeding in some females at South Georgia is a consequence of environmental change, but at the moment we are not sure if this is related to weather, a change in oceanographic conditions or food availability to which only some birds are responding.”
Source and Images: British Antarctic Survey