S Pembs choughs - a poor season but an incomplete picture so far

Noted Greg's chough summary for Ramsey. It is still a little too early to determine the outcome in South Pembs because access is not yet possible to check 8 sites in part of their range at Castlemartin. But of 13 nests known to be active between Tenby and Angle, so far 17 young have fledged from 10 nests (av 1.7 per active nest). So yes, lower that on Ramsey, and even poorer if the 3 failures are taken into account! The remaining 8 sites will hopefully boost the average a bit as all nests were known to be active with young being fed a few weeks ago. Suffice to say that (unless the unknown sites provide a welcomed boost) this year is set to produce the lowest average fledging success per nest for more than a decade. The season has been a longer one too - the earliest nest to fledge young (Stackpole) was in first week of June (typical date), the last (Lydstep) was only this week (two weeks later than usual at this location).

The poor chough season is almost certainly due to a number of related factors. There have been few new birds entering the breeding population due to poor survival of young in recent years. This was not helped by a very cold frozen spell last winter. January soil temperatures measured at a depth of 10 cms at Stackpole weather station fell to just below freezing for about a fortnight - the lowest soil temps recorded here since our weather station was installed a few years ago.

A number of choughs almost certainly starved during this cold spell, probably unable to feed properly in some places. Then we experienced a cold and very dry spring (still very dry!), when the limestone soils in particular became quite arid. Choughs may have found it difficult to find sufficient soil inverts during the spring and small brood sizes were a predictable outcome unfortunately. So let's hope that post-fledging survival will be much improved this summer. It will certainly be interesting to compare the whole of Pembs chough breeding records when they are available.

Does anyone know what the chough breeding outcome was on Caldey this summer?