Caribbean Migration

Connecticut Warbler (Oporornis agilis)

On October 8, 2002 I was on the MV Century taking a Caribbean cruise. While on the leg from St. Thomas to St. Martin I came up on deck around 10 PM EDT and saw small birds flying along with the ship and illuminated by the ships deck lights, which were very bright. The birds flew in and out of the lights of the ship and seemed to be warblers. I turned on my handy GPS and went down for my Camcorder. For over half an hour I videoed the flock of birds. At any one time about eight were visible. During this time I came across a warbler that seem exhausted sitting on the deck below the stack area, around which the birds were flying. It seemed to be a Connecticut Warbler.

The ship was traveling eastward at 11 mph and the birds seemed to fly easily along with it. Some, getting somewhat ahead, would turn back and take position again alongside the stack in the stern area.

The Caribbean (click on map for larger copy)

Virgin Islands (click on map for larger copy)

The following are some screen captures from the video I recorded. The camcorder had a 18x optical zoom which I was using without a tripod.

This is a view upward just in front of the stack. Five birds are visible.

Another wide angle view

Here is an mov clip(6.2 Mbyte) video of the above view.





The deck lights of the MV Century

another cruise ship about a mile away

When I used my camcorder to record the warblers and only used the built in microphone during the recording, I did not expect to have any recognizable sound. The wind during the recording was not that strong but played havoc with the sound track. So it was with some misgiving that I analyzed the sound track with a sound editing program. Surprisingly I noticed at least 21 vocalizations on the four minutes of recording. They seem to be associated with the images of the birds on the tape. I can not hear them (my high frequency hearing is very poor) but my brother and wife say they hear them clearly on playback of the tape.

You can download 22 seconds of the tape here. It is very large (1.87 Mbyte) so be patient. The excerpt has been filtered to remove much of the wind noise and to amplify sounds greater than 4 kHz.

I have included some sonagrams of the calls.



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                                                                                                Gregory J. Kunkel