Wednesday, 5 August 2015

Identity crisis

As in recent years, the mid summer period has been dominated by a nightjar population study at Brechfa Forest with a view to better understanding any potential effects of wind development. This is in association with Tony Cross who initially worked at the Brechfa site for many years before taking on two other intensive projects at sites in South and Mid Wales see

Whilst trying to catch nightjars for ringing and radio tagging, it is very common to catch a few swallows going to roost in the sitka stands during late July and August, though we have never caught a house martin. So whilst extracting a white-rumped hirundine from a mistnet last night I thought -  oooh a new species of by-catch for Brechfa! But as it changed angle it began to look more swallow-like. After a brief bit of even more excitement, I thought "what about a juvenile red-rumped swallow?!" but this idea was quickly quashed by the lack of any collar, so hybrid house martin x swallow it had to be,

The back end looked very much like a house martin with a deeply forked tail

The front end was more like a swallow though the amount of red above the bill was much reduced and the gorget was very pale

The feet were much paler than on a swallow with the faintest trace of the white feathering found on a house martin

Back to what I should have been doing, the nightjars are nearing the end of their breeding season, which has been a challenging one for them in terms of weather. There have been prolonged unseasonal cold snaps in the first half of June and late July and some very low night time temperatures e.g. 4.5degC last week. The wind has also been an issue with very few nights suitable for netting making capturing adults for radio tracking difficult. Nevertheless, the study has gone very well and productivity looks set to be very similar to the last two years largely due to lower levels of nest predation than usual compensating for any losses due to bad weather. One of the most satisfying moments of the study is when at the final nest visit, the fledged young are sat tucked up with an adult.

Adult female and two juvenile nightjars

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