As part of my decision to start recording birds this year, I also decided to try
start recording migrating birds over my apartment in central Stockholm. Yeah, I
know I should have better things to do, but this is fun. Bear with me! This
summer I bought a small Sony PCM A10
recorder, which I think is an excellent lightweight recorder, to have with me
in the field. In mid July I started to leave it outside my window over the night,
recording for the entire night. I have been doing it regularly since then every 2
to 4 nights.
Figure 1. The view from my study room window, outside of which I place
my recorder.
The cult of listening to and recording night migration of birds is called
nocmig, which is short for nocturnal migration and the act of doing it
can be called nocmigging. It sounds a bit suspect and nothing you would want
talk about with your friends, with police officers around. But Nocmigging is
not only fun and legal, it is also an excellent way to sharpen your skills in
identifying bird calls and enjoing the magic of bird migration.
The day after a nightly recording, I import the recording into the sound
editing program Audacity, and then visually
browse through it, looking at one thirty-second window of the sonogram at a
time. It takes about half an hour to an hour to browse through an eight hour
recording. When I see an interesting pattern in the sonogram, I listen to what
is recorded and try to identify the sound that produced the sonogram pattern.
In the beginning I listened a lot to cars, human voices, squeeky doors and bikes
as well as the odd drunkard or boisterous gang of urban hipsters. But quite
quickly, I got good at visually sorting out the normal urban noises from bird
calls in the sonogram patterns. And just as quickly I started to be good at
recognizing the sonogram signatures of common birds like Blackbirds (Koltrast),
Turdus merula, Swifts (Tornseglare), Apus apus and Blue tits (Blåmes),
Cyanistes caeruleus. Then I started noticing other patterns, such as the time
in the morning when different species start getting active, but also, as the
weeks passed by, that some species started disappearing from the recordings,
like Swifts in late August. And Baltic Lesser black-backed gulls (Silltrut),
Larus fuscus, that start migrating south in late September to the Arabian
peninsular and east Africa, where they spend the winter.
Figure 2. The sonogram, as produced in Audacity, of a Brambling (Bergfink),
Fringilla montifringilla, recorded at 06:28 on September 28, 2020. It probably
took a rest on our roof top, on its migratory voyage south!
As summer turned into autumn some of the summer birds disappeared, but in late
August, migrating White wagtails (Sädesärla), Motacilla alba, Meadow pipits
(Ängspiplärka), Anthus pratensis and the odd Tree pipit (Trädpiplärka), Anthus
trivialis started to feature in my nocmig recordings. Then in mid September the
recordings turned eerily silent for a week or so. Just the odd White wagtail and
confused Siskin (Grönsiska), Spinus spinus, where recorded. That was until
the night of September 28, when suddenly the flood gates of migrating Redwings
(Redwing), Turdus iliacus, and Song thrushes (Song thrush), Turdus
philomelos, where opened, and I recorded my first migrating Brambling! Oh, the
simple joys of life!
Recording 1 In the beginning, a single sharp tsip call of a Song thrush
at a distance, and then the stiyyf calls of two or three passing Redwings.
Recorded at 03:04 on September 28, 2020.
Recording 2 The squeeky call of a tired Brambling taking a rest on the roof
of our apartment building in central Stockholm. Recorded at 06:28 on September
28, 2020.
To give an example of the impressive night migration over my apartment on
September 28, here is the logfile for that night. I make a note of every migrating
bird that I identify in the recording, but for non-migrating birds, I just make
a note of the first bird I hear. Calls I don’t recognize, I call Strangies and
I usually add a short note on the strangie, in case I want to go back to it and
try to figure it out.
Equipment: Sony PCM-A10
Placing: Window sill in study room
Time: 2020-09-27 22:50 - 2020-09-28 07:0
Weather: Clear with light easterly breeze (3 m/s). Light fog in morning 10-13 C.
Comments: Autumn is here for real! Thrush bonanza! 52 Redwings! 46 Song thruses!
The first Brambling!
Log:
22:50 Strangie (descending spizzz from 9,0 -> 6,5 kHz
22:53 Redwing
22:58 Redwing
23:02 Redwing
23:11 Redwing
23:12 Redwing
23:14 Redwing
23:18 Redwing
23:19 Strangie (descending spizzz från 7,0 -> 6,0 kHz)
23:31 Strangie (descending spizzz från 8,5 -> 7,0 kHz)
23:39 Redwing
23:46 Redwing
23:50 Redwing
23:56 Song thrush
23:59 Song thrush
00:02 Redwing
00:03 Song thrush
00:09 Song thrush & Redwing
00:13 Redwing
00:18 Redwing
00:20 Song thrush
00:31 Redwing & Song thrush
00:33 Redwing
00:38 Song thrush
00:38 Redwing
00:42 Song thrush
00:45 Redwing
00:49 Song thrush
00:57 Strangie (High pitched call 9,0 -> 8,0 kHz)
01:03 Redwing
01:04 Fieldfare (Squeeky nasal call)
01:07 Redwing
01:10 Song thrush
01:11 2 Redwing
01:14 Redwing
01:28 Redwing
01:30 Song thrush
01:31 2 Song thrush
01:35 Redwing
01:38 Song thrush
01:39 Redwing
01:48 Redwing
01:49 Redwing
01:51 Redwing & Song thrush
01:53 Redwing
01:56 Redwing
01:57 2 Redwing
01:58 Redwing & Song thrush
01:59 Redwing
02:12 Redwing
02:17 Redwing
02:19 Song thrush
02:21 Song thrush
02:22 Redwing
02:25 Song thrush
02:27 Song thrush
02:30 Song thrush
02:31 Strangie (High pitched call with intriguing sonogram 8,5 -> 7,0)
02:32 Redwing
02:34 Redwing
02:43 Song thrush
02:44 Redwing
02:46 Redwing & Song thrush
02:49 Redwing
02:52 Strangie (Meadow pipit?) & Song thrush
02:58 Strangie (1 high pitched call) & Song thrush
03:00 Strangie (like 00:57)
03:01 Redwing
03:03 Song thrush & 2 Redwing
03:08 Song thrush
03:11 Song thrush
03:17 Redwing & Song thrush
03:23 2 Song thrush
03:25 Redwing
03:29 Song thrush
03:31 Song thrush
03:33 Redwing
03:35 Redwing
03:38 Fieldfare (Squeeky nasal call)
03:41 Song thrush
03:44 Song thrush
03:45 Redwing
03:47 Song thrush
03:48 Song thrush
04:07 Song thrush
04:50 Song thrush
04:50 Redwing
05:13 Redwing
05:20 Blackbird & Song thrush
05:41 Strangie (High pitched srrrr, thrushy)
06:00 2 Song thrush
06:10 Song thrush
06:16 Brambling
06:25 Hooded crow
06:33 Song thrush
06:45 House sparrow
06:51 Song thrush
06:52 Blue tit
06:53 Siskin
06:53 Great tit & Magpie
06:54 Song thrush