When I was a kid, my father – the late Dr William ‘Bill’ Burnham - was involved with the captive breeding of between 200 and 300 peregrines annually – birds that were released into the wild throughout the US,” said Kurt.
“I was surrounded by falcons on a daily basis and one of those ‘weird’ kids who loved what their father did and wanted to do exactly the same.” Kurt has spent nearly three years of his life conducting avian research in Greenland – mainly on peregrines and gyrfalcons but also on Arctic terns, eider ducks, black-legged kittiwakes, little auks and other species. But some of the most interesting studies and findings have centred on the gyrfalcon – a popular falconry bird in the Middle East and elsewhere.
In a paper published in 2011 in the scientific journal Ibis, Kurt – president of the US-based High Arctic Institute (www.higharctic.org) - revealed that high Arctic gyrfalcons spend long periods during the winter months living and hunting far out to sea on pack ice.
“There had been a number of studies of gyrfalcon populations in the summer, but nobody knew what these birds did and where they went in winter. Most Icelandic gyrfalcons are resident all year round. In the Thule area of north-west Greenland, however, there are not a lot of birds of any kind during the long, harsh winter when it is dark for three months.”
Satellite tagging of 48 gyrfalcons in Thule, Kangerlussuaq (central western Greenland) and Scoresbysund (central eastern Greenland) found that certain birds ranged far and wide during the Arctic winter, living and hunting for weeks at a time far out to sea.
“Several birds we tracked didn’t have any obvious winter home ranges and travelled continually, at times spending up to 40 consecutive days at sea,” said Kurt.
“During these periods away from land, the gyrfalcons probably rested on icebergs and fed on seabirds. It had previously been thought that gyrfalcons flew out to sea to feed for a day or two and then returned to land, before doing the same thing again. “Nobody had realised that the ocean itself, and the icebergs within it, were a viable winter habitat and one that was being utilised by gyrfalcons for extended periods.”
A juvenile female gyrfalcon flew 4,548 km in roughly 200 days one winter, spending half that time over the ocean between Greenland and Iceland. “Although we don’t know for sure what gyrfalcons are feeding on when they are away from land, I guess that in most cases they will be taking little auks and black guillemots, both of which are really common birds in north-west Greenland.
“If you are a gyrfalcon flying over the ocean, you don’t want to try to catch something too large in case you end up in the water. Seabirds can float on the ocean and are designed to get wet, but not gyrfalcons!”
The satellite tracking data threw up all manner of interesting statistics about gyrfalcon movements during both summer and winter.
The breeding home range area for seven adult females varied from 140 to 1,197 sq km but for two adult males was 489 to 503 sq km.
Outward migratory journeys from breeding to wintering quarters were recorded for three gyrfalcons. An adult male flew 3,137 km in 38 days from northern Ellesmere Island, Canada to southern Greenland, an adult female flew 4,234 km from Thule to southern Greenland via eastern Canada in 83 days and a second adult female travelled 391 km in 13 days from Kangerlussuaq in central western Greenland to southern Greenland.
It has also been discovered that one cliff nest in Greenland has been used by gyrfalcons for a staggering 2,500 years, while three others are each over 1,000 years old. The great age of these nests was determined by carbon dating the guano left behind by countless generations of birds. “Although these nests are not used every single year, they have nevertheless being in more or less continuous use since they were created. The guano in the oldest nests is over a metre thick – itself an indication of the great age of these structures.”
In the early 1970s there was roughly the same number of peregrine and gyrfalcon pairs in central west Greenland. But by the mid-2000s there were12 to 15 times as many peregrine pairs. “There has been a huge increase in peregrine numbers for climatic or other reasons and this is bringing the two species into direct conflict for nest sites and for food.
“If you approach a peregrine’s nest, the birds become extremely aggressive, they ‘cack’ and they are probably going to stoop. But if you go to a gyrfalcon’s nest, the birds simply ‘cack’ and frequently fly off. They rarely stoop. Gyrfalcons are much less aggressive than peregrines – more mellow you could say.
“Peregrines are much manoeuvrable in the air than gyrfalcons – the difference, you could say, between a Ferrari and a truck negotiating an obstacle course. The peregrine wins every time. I’ve seen peregrines strike and hit gyrfalcons and the two birds tumble for thousands of feet with their talons interlocked.”
One new area of research for Kurt and his High Arctic Institute is finding out what gyrfalcons eat when they first return to their nests. “Until now we haven’t arrived at nest sites, because of the weather, until the breeding season is already well under way and the chicks are two or three weeks old. We are hoping to get a couple of researchers into Thule very early in the year when the ocean is still frozen to see what prey is being caught when the gyrfalcons first return.” Added Kurt: “Gyrfalcons are pretty incredible birds. They are top predators and superbly adapted not just to survive but to thrive in some of the harshest conditions in the world.”

Main Page	Page Up
عربي