Thursday, 15 July 2010

Frustrating finds

Studying storm-petrels, one spends much of their life like this...



Or this...

Or this...



There doesn't seem much chance of spotting anything of interest, when you spend your life with your head buried in a wall. The orcas are probably leaping out of the water, dancing around in their full glory, while we remain completely oblivious.

Nights are spent, often frustratingly, searching for nests. Breeding sites are most easily found by listening for singing birds at nights. First you locate the approximate area of the sound, then quietly you get down on your hands and knees and press you ear up to the many cracks and crevices between stones or boulders, one by one, until you can locate the exact point of the call. Then, turning the torch on, you shine it into every gap available and hope that the beam of light eventually falls upon a bird. The response of birds to the torch-light is to either shut up instantly or start alarming at you. I’ve learned that I can communicate with them by mimicking their alarm call, precipitating repeated calls from them. The continued calling facilitates finding the bird, though on most occasions, you have to give up, knowing that the bird is buried deep down in the wall or beach, far out of sight. Maybe about 1 in 8 nests are visible and, even then, quite how much of the nest site or bird you can see is another matter. And, on top of this, we are limited to a narrow window of maybe 2 or 3 hours of darkness (highly variable depending on cloud cover) during which stormies are active and singing vigorously. Ideally, we are trying to find as many accessible nests as possible, such that, later in the season, chicks can be removed from the nest site enabling us to record biometrics and monitor growth rate of chicks in relation to visitor pressure, egg neglect and provisioning rate.

Nests are then re-located during the day to further investigate visibility and accessibility and to check for daytime occupancy. This can be further complicated by things such as cheeky gull chicks obstructing entrances to nest sites!

A cheeky great black-backed gull chick hiding in the entrance to a storm-petrel study nest!
(Hannah Watson)

Where possible, temperature loggers are deployed in nests to remotely monitor adult attendance and egg neglect during incubation. This often involves tearing your hands and arms to shreds as you try to squeeze your arm as far into a crack in a wall and have to use the sense of touch alone to excavate a suitable spot to embed a temperature logger. Then you pray that the bird will lay its egg on the temperature logger. Temperature loggers have been embedded into an artificial nest cup, moulded out of clay, with the hope of making a perfect depression to entice the bird to lay its egg in. We have had some success so far and certainly some birds and eggs have been seen sitting happily on loggers. We just need to convince a few more that our clay modelling skills produce a desirable home for their egg!

A neglected egg sitting on an artificial clay nest cup with a temperature logger embedded in it
(Hannah Watson - taken on my phone, hence not very good!)