Sunday, 5 June 2011

Yellow Heads

PhD student Bethany Hawkins spills the beans on what has been capturing visitors interests for the last few weeks on the island:
"Recent visitors to the Isle of May may have noticed an increase in numbers of a rare sub-species of the black-legged kittiwake known as the yellow-headed black-legged kittiwake (Rissa tridactyla aurocephalus). These birds can be distinguished by their yellow heads which vary from a pale shade to a striking golden colouration. The first sighting was on the evening of the 25th May and since then a total of 48 individuals has been recorded...Ok, so before all you twitchers set off on an epic journey to this windswept island off the East Neuk of Scotland just to get another ‘tick’, I’ll admit that our local yellow-headed black-legged kittiwakes are in fact the result of my very own artistic handiwork. I’ve been catching individuals in order to take measurements to help me understand the condition of the kittiwakes breeding here on May. Body condition may link food availability to breeding success, helping us to better understand why this species is declining. Once caught, ringed and measured, I’m marking my kittiwakes with yellow dye so that I can spot which ones I’ve caught without having to re-catch them and read their tiny metal rings. I actually think they rather like having their heads painted...I guess it’s not unlike going to the hairdressers and having your hair washed and head massaged...and I pay good money for that! Quite what the kittiwakes’ other halves think when they return to the nest I can’t be sure, but so far I’ve not seen any hair-style induced domestics. The only trouble with the dye is that the kittiwakes have a tendency to go for a wash in the sea after being handled by a human (I don’t blame them to be honest, judging on the shower restrictions of 1 shower a week out here!) and therefore wash off most of the hair dye along with the human filth. So, individuals with a good sense of personal hygiene aren’t as easy to spot from afar compared to those that are clearly embracing the culture of minimal washing adopted by us researchers. I’m hoping to re-catch the yellow-heads so that I can compare body condition of individuals early in the breeding season with later in the season to see whether they are in poorer condition after the stress of raising their chicks. However, the success of this re-capturing depends on how cooperative the yellow-heads are feeling when I approach them once again, armed with my ruler, scales and a paintbrush!"

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