Ringing and measuring Madeiran storm petrels
From the 13th to the 15th of November 2013 Catarina & Hugo joined a research team formed by Vicent Bretagnolle, Frank Zino and their life companions, respectively Sabrina and Elizabeth. The aim was to study the winter colony of Madeiran storm-petrels by catching them on mist nets and take as much information as possible, such as biometric data, blood samples and photos.
The three couples sailed to Deserta Grande onboard Oceanodroma RHIB, on the afternoon of Wednesday 13th. The sea was choppy but the skipper (Catarina) managed to get us all safely to Doca at Deserta Grande. On the way we saw 2 Fea’s/Desertas’ Petrels and a few Cory’s shearwaters. After disembarking and settle at the Madeira’s Natural Park house, the mist nets were put up as the sun was already setting down.
On Wednesday night, from 21:00 to 2:00 with a short stop for dinner in between, we managed to catch, weight, measure, take blood and photograph 20 Oceanodroma castro.
On Thursday late morning we all went up to Deserta Grande with Ricardo Rodrigues as a guide, one of the Natural Park of Madeira wardens. At the top of Deserta Grande we watch a Pacific/American Plover (by the call and underwing it was not an European), a Hobby and a Short-eared Owl.
By the evening the nets were again put up and just between 19:00 and 12:00 there were 30 non-ringed O. castro caught on the net. Interesting that the nets were put on the same spot as the night before and none of the previous 20 ringed birds were caught again. t was 2 very profitable nights!
From some of the photos we took to the tail of some Oceanodroma castro we can see that some have slightly forked tail while other have it plain. This observation goes against that theory that the shape of the fork may distinguish between a winter or summer breeder.