Monday, 9 July 2018

Castlemartin peninsula - a pretty good chough breeding season here but will the hot dry weather impact post-fledging survival?

Along the Castlemartin peninsula (within the Castlemartin Coast Special Protection Area) all known successful chough nests (12 out of 16 where breeding was attempted) have fledged a reasonable number of young (at least 32 in total). Some young are already becoming independent of their parents.

In south Pembs overall, despite some early concerns, the breeding season was only a little later than average. However information from Jane Hodges (who coordinates the monitoring of chough sites in mid and north Pembs) paints quite a different picture "....I haven't known a fledging season quite like this one. It has been incredibly frustrating and hard work...a very protracted and late season with failures and/or young disappearing quickly after fledging...".

Watching young choughs begging for food from the adults on the Castlemartin peninsula on Sunday (and some young feeding themselves) suggested that some at least are currently finding it very hard work to find food in the heat. The Limestone soils are generally very dry and baked quite hard, probably making it difficult to probe for soil invertebrates in some areas at least.

Almost constant begging calls from young chough are typical along parts of the coast at this time of year

The youngster was eventually fed a chunky beetle (most probably a summer chafer) 
Not unexpectedly, most choughs observed were tending to concentrate on surface insects in the grassland. Particularly numerous and clearly being eaten were summer chafers, some other small unidentified beetles and various Hymentoptera present among wonderful displays of greater knapweed and other flowering plants.

This almost independent youngster had some difficulty swallowing this summer chafer
It will be interesting to see how many young survive possible starvation etc during the continuing hot, dry spell and go on to form post-breeding season feeding and roosting flocks later in the summer/autumn period. Reported sightings of chough flocks during August/September would be welcomed by Jane and myself.

Thanks also to Lynne Houlston, Graham Clarke and Paul Culyer who contributed valuable breeding site observations on the Castlemartin peninsula.

Bob Haycock and Jane Hodges