One of the least-well-known breeding species on the island of Skokholm, off the Pembrokeshire coast, is the European Storm-petrel. Storm-petrels return to their nest sites on land mostly under cover of darkness, so they are not an easy study species.
To help study the population (which is estimated to support 1,910 occupied sites), an artificial Storm-petrel wall was built in 2016. On one side it looks like one of Skokholm’s ‘herringbone’ walls, but this very special wall contains over 100 Storm-petrel nestboxes with access hatches. Nicknamed the ‘Petrel station’, this allows more detailed monitoring of the breeding pairs which use it.
Chris Payne applied to the British Birds Charitable Trust for a grant to assist with work installing infrared cameras into some of these chambers in an attempt to learn more about the breeding behaviour of these popular yet secretive birds.
Storm-petrels are particularly susceptible to disturbance and will readily abandon their nests, so all camera equipment had to be in place before they returned to Skokholm. The chambers to hold the cameras were chosen and all the equipment installed by the beginning of April 2019. This was a technically challenging project; a solar power system and six boxes of connectors were required for each chamber in addition to the cameras themselves, plus a master control box triggered by any bird movement. Hurricane Hanna did not make matters any easier!
Once all the equipment was in place it was a matter of waiting; for the Storm-petrels to return, to see if any of them chose a nesting chamber containing a camera, and to see if the equipment had survived the harsh environmental conditions.
Being sensitive to the need to avoid disturbing the Storm-petrels, Chris made a very limited number of visits to the Petrel Station over the course of the breeding season. On his visit at the end of July he was thrilled to see that stormies had taken residence in at least one video link chamber and saw a Storm-petrel chick, with remnants of eggshell, for the very first time in the study wall. This brought much excitement to many of the people connected to the study wall, especially Richard Brown and Giselle Eagle, the two wardens whose idea it was to build it in the first place.
Subsequent visits yielded superb infrared video footage of a parent bird arriving and feeding a small chick. As far as we know, this is the first footage of its kind using infrared cameras to record an adult bird feeding a chick on the nest. One interesting observation made by Chris is that on arrival the parent bird did not feed the chick straightaway but groomed and brooded the chick for a while. The chick had been on its own for some time and was, we assume, chilled. It was unresponsive initially until warmed by the parent for around 20-30 minutes before being fed. Whether or not this is the norm for Storm-petrels has yet to be determined.
The latest news from Skokholm is that there are now three Storm-petrel chicks in the wall. Chris plans to return there next spring with improved technology and new knowledge of the petrels’ nesting habits and we are very much looking forward to seeing the results of his endeavours.
“Grateful thanks are due to the two wardens on Skokholm, Richard Brown and Giselle Eagle, for giving me the encouragement and opportunity to undertake this challenging project, along with financial assistance from the British Birds Charitable Trust.”
This report was first published in the September 2019 British Birds e-newsletter (Issue 53)