Climate change affecting breeding habits

Breeding habits evolve London - Arabstoday   Flying around the Southern Ocean is one of the largest bird species on Earth, the Wandering Albatross, also known as the Snowy Albatross or White-winged Albatross. They are a predator and keystone species of their circumpolar range. Like all polar species, they are feeling the effects of a warming climate, and it is beginning to cause some very fundamental changes to their behavior. Typically, the Wandering Albatross lay their eggs between December 10 and January 5, at the start of the Southern Summer. A new study from the British Antarctic Survey (BAS) has shown that these breeding times have been slowly inching back. Breeding habits for this bird have been cemented over time through many generations of evolution. Every other year, the Wandering Albatross return to one of several colonies on isolated islands in the Southern Ocean. These include the South Georgia Islands, Prince Edward Islands, Marion Island, Crozet Islands, Kergulen Islands, and even Macquarie Island. There are an estimated 26,000 in the wild. The monogamous adults lay one egg between December 10 and January 5, of which only 30 percent survive to breeding age. These birds typically do not breed until age 11-15. The BAS study found that the average egg laying date has moved back by 2.2 days earlier within the last 30 years. Specific reasons for this change remain unclear. According to lead author, Dr. Sue Lewis at the University of Edinburgh's School of Biological Sciences, "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 egg. 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." BAS researchers monitored nest sites on Bird Island, part of South Georgia during pre-laying, laying, hatching, and fledging periods. The birds have taken a special interest of late. Their numbers have been dropping because they swallow baited hooks from fishing vessels, are dragged under and drowned. Reasons for the shift in behavior include a wide range of environmental changes. However, the BAS researchers are unsure if this is related to changing weather, changing oceanographic conditions, or changes in food availability. This study was funded by the Natural Environment Research Council (NERC) and published in the journal, Oikos.