Nocturnal Migration
Recording nocturnal flight calls: a beginner’s Experience Phil Whittaker Since 2018 I have been recording bird calls in the night sky on favourable evenings from my garden in the Gipping Valley in Mid-Suffolk. My recording sessions have focused on the spring and autumn months, or occasionally in response to weather events that might perhaps induce weather-related movements. Migrating birds fly over Suffolk on a broad front and it is not necessary to live on the coast, or a migration flyway, to be involved in recording nocturnal flight calls. I must stress that I am not expert at this activity; there are many other enthusiasts involved in this who have a better knowledge and skill at identifying calls and reading spectrograms and processing than I have! I am very much a beginner on a steep learning curve with much still to learn. The process has become known, and abbreviated, as Nocmig or NFC (Night Flight Calls) and more and more birders are becoming involved nationally and internationally in night-time recording from gardens, in both urban and rural areas. It is easy on autumn evenings to sit in your garden and pick up by ear the ‘tseee’ calls of Redwings Turdus iliacus passing over for short periods of time, but much less easy to cover a full ten hours of passage through the night. Nocturnal recording can fill an important gap in our knowledge of the fascinating phenomenon of bird migration. Night flight recording allows analysis of a full night of calls at leisure on the following day or whenever you please. It is essentially birding whilst you sleep! Equipment and Recording Many birders I have talked to about my experiences have said that it sounds “too technical” or” I’m no good with computers”. I must admit that I was initially cautious when I started, especially when I looked at a series of daunting-looking spectrograms and was confronted with the prospect of using audio processing software and recording hardware. It can, however, be quite a simple process, albeit a very time consuming one! There is also a wealth of online advice and support that helps considerably. You can start recording birds at night for free with a mobile phone (what can’t you do with a mobile phone?) and a computer using free, downloadable, Audacity sound-processing software. My recording set-up is quite basic, and cost-effective compared with some that I have seen. I use an HTDZ shotgun microphone, £20 from eBay, linked to a Tascam DR-05 Recorder, cost £70. I power this through the long hours of night with a Pebble ancillary battery which I have used for many years as a back-up to charge my phone. I did a bit of DIY to fit the microphone in a plastic pipe with an attached spike that temporarily fixes it into the ground. I put the recorder in a weatherproof bag, switch it on and leave it out, usually, from just after sunset, often until past dawn. A computer/laptop is required for the processing of the resulting recording and, although not essential, a set of headphones can be useful, especially with faint, or distant, calls. I find it useful to have a good set of external speakers linked to my laptop which allows additional volume control of faint calls. I have experimented with linking up my microphone to dustbin lids, large flowerpots and mixing bowls to try and replicate a parabolic reflector and improve signals from the night sky. As there was no discernible improvement, I now just use my shotgun microphone as a stand-alone (see picture below). A Parabolic Reflector is the, ‘state of the art ‘, microphone for capturing bird calls; I might get one if my interest develops, but they are expensive! All of the equipment that I use is easily transportable and can also be used in the field for daytime recording.
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