Birds controlled on Nan Ron on 22.07.2007
2545743
2546661
2565379
2565932
2586507
2588440
2510852
2626714
2557082
2572538
2575506
2587324
2518884
2545564
2531583, 2531550
both from // 23.07.2001 // Nan Ron
2546641
2573682, 2573569
both from // 18.07.2003 // Nan Ron
2583656
2586649
2587344, 2587547
both from // 20.07.2004 // Nan Ron
2588742
2559216
2571936 // 11.07.2005 // Fife Ness, Fife Region 275km 338d
2522406 // 10.08.2005 // Handa, Sutherland 54km 70d
All from // 21.08.2005 // Faraid Head, Highland Region 27km 103d
2584299 // 16.07.2006 // Eilean Hoan, Durness 21km 96d
2584264 // 23.07.2006 // Nan Ron
(and also // 16.07.2006 // Eilean Hoan, Durness 21km 96d)
2510735 // 04.07.2006 // Faraid Head, Highland Region 27km 103d
2510739 // 04.07.2006 // Faraid Head, Highland Region 27km 103d
(and also // 23.07.2006 // Nan Ron)
2548060 // 06.07.2001 // Sanda Island, Kintyre, Strathclyde 373km 12d
2572503 // 19.07.2003 // Nan Ron
(and also // 05.07.2004 // Faraid Head, Highland Region 27km 103d)
2495622 // 18.08.2005 // Isle of May BO, 284km 339d
2558231, 2504570, 2504489,
All from // 21.08.2005 // Faraid Head, Highland Region 27km 103d
2558262 // 21.08.2005 // Faraid Head, Highland Region 27km 103d
Incidents of a seabird preying on colonies of another species at night may be unique to a remote islands archipelago.
Ecologist Will Miles said initial research of great skua preying on Leach's petrel on St Kilda found the behaviour was unlikely to be common.
The National Trust for Scotland (NTS) has been recording "alarming" falls in the smaller petrels on the islands.
Mr Miles and fellow researchers used night vision gear to observe the skua. NTS said the Leach's petrel colony on St Kilda, which it owns, is the largest in Europe and numbers about 40,000 pairs. Researchers from Glasgow University have been investigating suggestions that great skua, or bonxie, may be eating up to 14,000 petrels every year. The research on Hirta, St Kilda, will run until 2009.
Results of this year's work are still being analysed, however, Mr Miles revealed some intriguing insights into the bonxies' behaviour. He said: "The skuas are highly active on the petrel colonies at night and catch petrels in a variety of ways - both on the ground and in the air. "Nocturnal foraging by great skuas is thought to be quite a rare situation. "At least, it has not been widely reported from the most intensively studied skua colonies on Shetland or from elsewhere across the species' breeding range. "The situation on Kilda seems rather unique in this respect."
Why the bonxie prey on petrels may be down to a combination of factors. They include limited other food sources, competition between the skuas and when the birds nest close to petrel colonies. Mr Miles said: "Skuas are highly opportunistic predators and some individuals seem to develop a taste for certain prey types.
"One possibility may be that on Kilda the petrels are a relatively abundant prey type, a few individual skuas have exploited this situation opportunistically and their behaviour has been copied by others looking for an easy meal." After assessing the safety of vantage points, the researchers spent nights close to high cliffs, steep slopes and scree boulder fields. Mr Miles said: "Once on-site, we then stayed put in one watching position for the hours of darkness and just observed the bird activity."
Data gathered by researchers will be used to help guide conservation efforts for both species.
