Environmental and Social Research

John F. Kearney & Associates

METADATA

Microphone: SMX-NFC

<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 2017

Cape Forchu, Yarmouth County, Nova Scotia

Weekly Reports at Cape Forchu for the Autumn 2017


1st Week of August

 

This is the first report from the new Cape Forchu nocturnal migration acoustic monitoring station. The monitoring station is only a few meters from the coast.

There was a total of 166 flight calls recorded, representing an estimated 58 birds and 17 species. The most common species was unidentified terns. My initial searches of various flight call libraries would indicate that the calls were those of the Common Tern. It was estimated that the 91 tern calls recorded on the night of 4 August just after nightfall represented 12 birds. This is a conservative estimate that assumed birds were circling the station. However, since Common Terns begin their overwater migration just after sunset, it is possible the calls represent a higher number, perhaps up to 30, birds streaming past the station.

The most common land birds were Northern Waterthrush, Black-and-White Warbler, and American Redstart. The relatively few warblers at this coastal site contrasts with a considerably higher number at the Carleton station which is 30 km inland from Cape Forchu. This would suggest that inland areas provide more favourable stopover habitat in the early stages of migration and during post-fledgling dispersal.

However, two other factors may affect a comparison of these two sites. First, the Cape Forchu recording unit runs on battery power which results in an estimated 1/3 reduction in the power and reach of the microphone compared to the electric cord power source of the recording unit at Carleton. Second, it will take the better part of the migration season to determine if the recording unit at Cape Forchu is optimally located in relation to the local migratory pathways in the area.

A summary of the week’s nocturnal migration is summarized in the table below.



Estimated

Species

Calls

Birds

Unidentified Tern

91

12

Northern Waterthrush

13

10

Black-and-White Warbler

10

8

American Redstart

11

7

Blackpoll Warbler

5

3

Least Sandpiper

5

3

Magnolia Warbler

4

3

Canada Warbler

2

2

Unidentified Shorebird

4

2

Unidentified Warbler

2

2

Semipalmated Plover

2

2

Semipalmated Sandpiper

4

2

Yellow Warbler

3

2

Alder Flycatcher

1

1

Blackburnian Warbler

1

1

Chestnut-sided Warbler

1

1

Ovenbird

1

1

Spotted Sandpiper

5

1

Tennessee Warbler

1

1

Total

166

58