Monday, July 16, 2012

Nocturnat Listening - End May Update

Nocturnal Listening – End May Update

Just in case the technical stuff in the last postings put folks off and just to keep things going.... here a quick update on the birds during almost continuous overnight listening.  The last part of April and early May were washed out by the weather, not that it prevented migration (far from it!) but that it was just impossible to listen and unwise to try! When things got going again, thrushes had faded out and a lot of the wader passage over that time had been missed. More Oystercatchers, a few goidies, a Whimbrel, LRP and interestingly several Common Sands proving distinct nocturnal status. Still a few swamp birds audible in the overnight sky during the first part of the month with both Moorhen and Coot detected over land, miles away from any water. Cuckoos occasionally heard both in the night and sometimes in the dawn chorus. Passerines, whilst not so many identifiable to date, were interesting with quite a few unknowns requiring work when time available and experience gained... The most interesting finding tho was the very occasional contact calls from Swallows in the still and silent skies of the very early hours, in total darkness, hours before the onset of twilight and first robin of dawn. On two occasions quite high or distant, once then briefly quite close before silent again. Another occasion just a single double contact call and another with a bird heard contact calling for a few minutes before gone. Literature in some cases alludes to night migration cross seas and inhospitable terrain and subsequent arrivals at observatories at dawn, it also refers to night feeding in areas with artificial lights in the breeding season with adults bringing food to the nest in the dark, so the above listening observations are difficult to reconcile immediately... but keeping an ear to the situation as it presents its self. Enough to say that the first call, the single double contact call on the 5th May (actually the early hours of the 6th), initially unexpected and unrecognised was probably a moving migrant, as were maybe some of the others but more later on this after elapsation of time allowing further study. Occasional vis in the dawn chorus with flava wagtail detected on fly through, but generally and especially as the month has progressed the chorus has just become a terrible densely prohibitive, over modulated, raucous mat of sound, impossible to hear through and totally impossible to analyse.... thus emphasising the need re just one of the reasons to get your listening station as far away as possible from bird rich habitat with frequent close calling possibilities, where ever and whatever they are.... The chorus will however soon die back and mid/late summer and autumn should be workable at dawn and dusk, especially at open sites. I might just add that I am very much behind in analysing the overnight files so there will almost certainly be more to come when time permits. Some nights very little, but others, just like the pattern of vis, much better. After the trial this spring as an extension to my normal listening activities, I am now totally addicted to this automated form of listening, with unexpected arising and will be continuing on as conditions vary and permit through the year and running it parallel to the vis in the main season... really looking forward to listening through the night during a big thrush arrival, possibly even confirming one, and already have a calendar of other stuff ear marked for investigation. Other patterns of activity are also beginning to become apparent even with our brief study to date so it will be interesting to expand on and see how these develop in time.


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