'Nocmigging' on Lundy

As a recent inductee to the mysterious world of recording nocturnal migration (or 'nocmigging'), I took my trusty sound recorder to Lundy during a recent three-night stay, from 8-11 August. The small, battery-operated digital recorder was deployed from just before dark to just after dawn on all three nights, and I reviewed the resultant sound files on a laptop after returning to the mainland, using the free-to-download 'Audacity' software. This essentially enables you to scan recordings visually and to fairly rapidly pick out any potential bird calls to listen back to, without having to sit for hours-on-end listening to everything in real time – which would clearly be impractical, not to say unhinged! This takes a degree of patience and experience and some calls have to be let go, unidentified – much like some birds glimpsed distantly or in poor light during the daytime.

Such considerations notwithstanding, the results were striking. Apart from the expected locally breeding Manx Shearwaters, Oystercatchers and gulls, I recorded the calls of five wader species: Common Sandpiper and Green Sandpiper (both on two nights), as well as single-night appearances by Ringed Plover, Dunlin and Curlew. Of these, only Ringed Plover was recorded by day during my visit (also a calling 'flyover' bird). The third and final night brought the only evident passerine migrant, a Tree Pipit calling late in the night, just as dawn was about to break.

Click here to listen to the Green Sandpiper recorded on 8-9 Aug

Here is a graphical representation of the same Green Sandpiper calling as it flew over St John's Valley under cover of darkness in the wee small hours:

Spectrogram of calling Green Sandpiper 8-9 Aug 2020

 

Jamie Dunning, currently conducting PhD research into Lundy's much-studied resident House Sparrow population, also did some nocturnal sound recording during his post-Lockdown visit to the island in July. Though primarily focusing on Manx Shearwaters and Storm Petrels, Jamie's efforts also picked up Common Sandpiper at Jenny's Cove on 7 July, Common Scoter and Whimbrel overflying the Village on 12 July, and a Green Sandpiper over the Village on 30 July.

These experimental forays into nocmigging on Lundy give glimpses of the kind of results that more systematic night-time recording might deliver, particularly during the main spring and autumn migration periods.

Tim Jones