Environmental and Social Research
John F. Kearney & Associates
<Sampling format; 16 bit
<Sampling rate: 24,000 Hz
Recording Equipment: Song Meter 2
Analysis Software: Raven Pro
High Frequency Detector Settings
>6000-11000 Hz, 23-395 ms,
>Signal/Noise 25% Minimum Occupancy
>Signal/Noise Ratio Threshold 3.5 dB
>Block Size 4992 ms, Hop Size 244 ms, 50%
Low Frequency Detector Settings
>2250-3750 Hz, 35-325 ms,
>Signal/Noise 20% Minimum Occupancy
>Signal/Noise Ratio Threshold 4.0 dB
>Block Size 998 ms, Hop Size 244 ms, 50%
Nocturnal Migration 2018
Including Morning Flight
Cape Forchu, Yarmouth County, Nova Scotia
Weekly Reports at Cape Forchu for the Spring 2018
4thWeek of May
outstanding event in nocturnal migration this week was the unprecedented
morning flight of nocturnal migrants, mostly warblers, at Tadoussac, Quebec, on
May 28th. An estimated 700,000 warblers were seen heading southwest along
the Upper North Shore of Quebec. There was considerable press coverage including
an article in the New York Times. This event confirms and sheds further light
on some of the characteristics of nocturnal migration at Cape Forchu this spring.
1. The birds at Tadoussac were flying away from the wide of
expanse of the St-Lawrence River northeast of Tadoussac toward the much narrower
portion of the river near Quebec City. This is consistent with the apparent reluctance
of nocturnal migrants to cross expansive bodies of water to Southwest Nova
Scotia in the spring.
2. The birds poured through the Tadoussac region (Saguenay) within
a short time frame in the last week of May. The number of nocturnal migrants at
Cape Forchu were 3 to 4 times greater in the last week of May compared to any
other week from late April onwards. Thus spring migration is highly concentrated,
especially as it pertains to warbler migration.
3. The very high number of nocturnal migrants at Tadoussac and the
very low numbers of nocturnal migrants at Cape Forchu in the spring migration
indicate that most boreal-nesting birds by-pass Nova Scotia in the spring,
migrating primarily up the mainland of the East Coast, much like shorebirds.
4. The huge number of birds arriving along the Upper North Shore
of Quebec throughout the morning is supportive of the observations at Cape
Forchu that more birds in the spring often arrived in the early morning hours
after sunrise rather than in the pre-dawn period.
Detailed information for Cape Forchu for the last week of May
can be found in the tables below.
3rdWeek of May
This week’s monitoring provided further evidence that more nocturnal
spring migrants arrive to coastal southwest Nova Scotia one to three hours
after civil sunrise than before first light. By civil sunrise on 18 May and 21 May
only 3 to 4 warblers were heard during each of these nights. In contrast, in
the 1 to 3 hours after civil sunrise, up to 19 warblers of 7 species and 27
warblers of 8 species were heard on these dates respectively during the 3 5-minute
count periods. Except for Black-throated Green Warbler and Yellow-rumped
Warbler, most of the warbler sounds heard were night flight calls rather than
chip calls or songs. This would indicate that these warblers were still on the
move. The migrating warblers included Blackpoll Warbler, Magnolia Warbler,
Yellow Warbler, American Redstart, Black-throated Blue Warbler, Blackburnian
Warbler, Common Yellowthroat, and Cape May Warbler.
The calls of a few Leach’s Storm-Petrels were again captured
this week. One of the best recordings can be heard here. If you have not heard this bird before, it is worth a
A flock of Common Terns were heard arriving at 2202 hours on 15
May. It was estimated that there were at least 11 birds, perhaps up to 30.
A chattering Baltimore Oriole was heard on the morning of 21
A rare bird of the week included a singing Field Sparrow. The
bird was heard at a distance throughout the morning of 21 May. One recording can be heard
Further information for this week can be found in the tables below.
2ndWeek of May
While remaining light in intensity, nocturnal migration
provided evidence of the arrival of early May warblers including
Black-and-White Warbler, Northern Parula, Ovenbird, and Common Yellowthroat. An
early Swainson’s Thrush was recorded at 0118 hours on 14 May and one was heard singing
at a distance the following morning; likely the same bird.
The offshore fly-by of the week was a single Leach’s Storm-Petrel
at 2340 hours on 12 May. The distant call of this petrel can be heard here.
The morning recordings reflected the arrival of warblers with
Cape May Warbler, Nashville Warbler, and Black-throated Green Warbler added to
the list of those noted in nocturnal recordings. The migration of White-throated
Sparrows remained strong but down somewhat in intensity from last week. With 24
species in the recordings for the week, it was the highest diversity so far
this year and was up 50% from the previous week.
Detailed information on the nocturnal and morning recordings can
be found in the tables below.
1st Week of May
Nocturnal migration was light again this week. White-throated
Sparrows and Savannah Sparrows made up most of the 35 calls recorded.
The morning recordings presented good evidence that many migrants
were arriving in the early morning rather than during the night. Recordings on
the morning of 5 and 7 May consisted of high numbers of White-throated Sparrow
flight calls. In both cases, calls were concentrated in the third hour after
civil sunrise (about 07:30-07:45 hours) with generally much fewer calls in
other hours. A total of 69 White-throated Sparrow flight calls were recorded
between 07:37 and 07:42 on 7 May. There were only 6 flight calls recorded during
the preceding night.
An American Oystercatcher was recorded flying past Cape Forchu
on the morning on 2 May at 00:12 hours. The justification for this
identification and the recording itself can be found here.
Detailed information on the nocturnal and morning recordings
can be found in the four tables below.
4thWeek of April
The number of nocturnal flight calls increased considerably
this week compared to the previous weeks of April. Nonetheless, total numbers were
quite light and may be due to a variety of factors including the lower density
of migration and higher flight altitudes in the spring, and a greater
reluctance to fly over the ocean in the early spring. For example, the strongest
nocturnal migration at Cape Forchu to date occurred when very light surface winds
(3-7 km/hr) over the Gulf of Maine on the night of 28-29 April may have allowed
birds to safely make a water crossing.
The species composition of nocturnal migration well
represented the spring arrivals in the morning counts; Hermit Thrush, Palm
Warbler, Yellow-rumped Warbler, White-throated Sparrow, and Savannah Sparrow
(compare first second tables below).
The frequency table for the month of April (4th table
below) shows some patterns in the timing of migration for various species. Golden-crowned
Kinglets and Song Sparrows peaked from April 11-20, Northern Flicker, Winter
Wren, American Robin, and Dark-eyed Junco from April 21-25, and Palm Warbler
and White-throated Sparrow from April 26-30 (and perhaps continuing into May).
The only rare bird for the month at the monitoring station was
the recording of about 9 Snow Bunting on the morning of 22 April.
Detailed information can be found in the four tables below.
3rdWeek of April
Nocturnal migration was again very sparse, but the few calls
marked the onset of the migration of Savannah Sparrows and Hermit Thrushes.
Morning counts heralded the arrival of Winter Wren and Palm
Warbler. There was an increasing loudness to the morning chorus of American
Robins, Song Sparrows, and Winter Wrens. Highest activity was on 19 to 21
All results for the nocturnal and morning counts are
summarized in the four table below.
2ndWeek of April