Hello,
Over the past several weeks I've been working on developing a new
nocturnal flight call recording setup at my house in the town of
Caroline. I've been using an old BirdCast microphone and filter system
since 1999, but over the past year that has become too unreliable. What
I am now using is a Sennheiser K6 omnidirectional microphone installed
within a parabolic reflector. This is connected to a Marantz PMD 661
digital recorder. The microphone is pointed at the night sky, on my
roof, and I record the entire night, storing them in 30 minute duration
files. I then store the entire night's recording (instead of the 3 sec
samples I got in BirdCast).
To identify the sounds I load a 30 minute file into Raven Pro 1.3 and
view the spectrograph. I scan the spectrograph very rapidly, looking
for long duration narrow frequency images (as compared to the very
short duration broad frequency clicks and other noises of drips etc).
It is not perfect, but at least I now have a copy of the entire duration
I was recording, and can provide these recordings for those interested
in more automatic NFC identification.
This is a long winded way of saying that over the past week I have been
recording a lot of birds (and other things). On two nights this past
week the rates were as high as what I get during a good night in Spring
migration. So far spectrographs of the birds I've recorded are similar
to those for:
Wood Thrush (one)
Veery (one)
Yellow Warbler (lots)
Louisiana Waterthrush (lots)
American Redstart (a few)
Ovenbird (a few)
Canada Warbler (a few)
Chipping Sparrow (one)
Grasshopper Sparrow (one)
Indigo Bunting (lots)
and many that I don't know what they are. I've also been recording quite
a few vocalizations between 8 kHz and 21kHZ, which I believe are bats.
The list of birds I've recorded during the past week is similar to those
I've recorded in past years at this time. What I think is interesting is
that the group appears to be a a mixture of birds in full long-distance
migration (like Yellow Warbler and Louisiana Waterthrush) and those
which may be exhibiting post breeding dispersal or very early migration
onset (like the restart, Wood Thrush, Indigo Bunting etc). One thing to
note is that all these birds breed on my property. Yellow Warblers bred
in my backyard, and they disappeared about 10 days ago. Nowt a group of
at least 1 adult male and 2 juv American Redstarts have been in my yard
the past few days. They bred in at least 2 places on my property above
my house (along a creek and in a 5 year old clear cut). I've not seen
them in the yard since Spring migration. It is a interesting coincidence
that I got a couple of redstart NFCs the night before they appeared in
my yard.
Anyway, it is my sense that passerine migration has begun in a big way,
and it is not too early to listen.
Steve Kelling
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