November 27, 2011

News from the Lundy Winter Trip, November 2011

Between 14th and 21st November, we sent a crack team of experts to Lundy to recapture or resight as many sparrows as possible for working out estimates of survival for this year’s fledglings and their parents. Here is an account by one of the group members, Isabel Winney:

We started the winter trip not knowing what to expect, and not daring to expect the successes to come. The weather was good, which boded well for our helicopter trip from Hartland Point to Lundy. It helped our nerves, too! For some of our team it was their first ever helicopter ride. The trip was uneventful and we got to the Marisco Tavern on Lundy in time for a bite to eat and a cup of tea before beginning to catch.

With so many sparrow experts on hand we had caught over 80 sparrows by the weekend, having worked morning, noon and even at night. We stayed at the Stoneycroft and Old Light Upper properties so there was always a warm lounge and comfy bed to return to after a hard day’s work.

For the weekend, we redoubled our efforts and doubled our bird totals! By the time we left we had caught more than 150 sparrows (a new winter record!). A few of them had escaped our ringing efforts this summer, and we were very happy to welcome those sparrows into the ringed population. A few other sparrows we caught this winter were as much as six years old (though some exceptional Lundy Sparrows have been known to reach 10 years of age).
Later in the week, we discussed sparrow science in the Tavern. First we got a presentation and later discussed Julia’s newly published paper on maternal effects on reproductive success. This even attracted a lot of interest from the Lundy staff, who asked insightful questions about father sparrow and his lack of contribution to successful reproduction. The paper also reveals that in 2000 to 2008, about one in eight sparrow chicks on Lundy was raised by a male that was not the real dad, - thus his female mate betrayed him! Those chicks are called “extra-pair” offspring.

Next, we discussed the major histocompatibility complex (MHC) diversity in sparrows. The MHC is the section of the genome responsible for the production of proteins involved in adaptive immune response in all vertebrates. The number MHC alleles an individual possesses dictate the pathogens they are resistant against, and therefore may have a direct impact on survival. The MHC is also considered a candidate locus for mate choice due to its role in immunity, - as any sparrow choosing a mate with a very different MHC is increasing the survival chances of its offspring by assuring it a grater ability to defend against pathogenes. MHC research in our Lundy sparrows revealed the surprising finding that there MHC diversity apparently plays no role in mate choice, but may be associated with chick survival. Also, it seems that MHC diversity changes over the course of years, which may indicate that different allleles are favoured in different years.

Isabel then presented findings from preliminary personality work, suggesting boldness may differ between male and female Lundy sparrows. Finally, Echo prepared a talk, given by Shinichi, which gave an overview of extra pair mate choice and social network analysis and the exciting role our Lundy Sparrows will play in these hot topics.

Talks over and sparrows caught, it was time to leave. It is always difficult to leave Lundy. The weatherman gave us hope by forecasting mist for Monday morning (in which case the helicopter would not be able to bring us back), but when the day came the mainland was in clear view. We set off for home with the last glimpse of Lundy’s southern cliffs lingering in our minds and a promise on all our lips to return in the spring.

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