Thursday, April 15, 2010

Hottest April Ever?

You may have read this blog entry about the wettest March ever. That was literally the case in nearly all of Connecticut this year. The early plant growth we predicted occurred. Now the state is currently working on the hottest April ever. The old phrase, "April showers bring May flowers" was off by one month. The March showers (or torrential rainfall!) brought us an abundance of April flowers. It seems clear the historical rainfall totals combined with warm, sunny weather (we are below average in rainfall thus far in April) is responsible for this. Nearly every type of plant is growing, flowering, or leafing out in southern Connecticut. We are about two weeks ahead of schedule in some places.

Have you seen a Palm Warbler yet?

So how about the birds? Judging from eBird, the CT birds discussion list, and word from friends of ours around the state, there have been pockets of migrants trickling in a week or two earlier than usual. There has not been a substantial movement of early birds. They are following their own clocks - namely the sun. They use day length as the primary gauge for migration. However, when this clock says it is time to move, there can be helpful factors. The warmth we have experienced has been a result of a southerly or southwest airflow. High pressure has dominated, keeping out storm systems and allowing this conveyor of warm air to get to us. The birds coming north for the breeding season can take full advantage of this southerly flow if the winds remain that way at night.

When migrants like this Yellow Warbler arrive in late April the foliage will not be so bare.

The first week of April was very cooperative, while the second week has seen variable winds. A rainy, cool, weekend should stop movement for the next few days, but next week will allow the floodgates to open to possibly the first sizable wave of passerine migrants. One also has to remember that our weather is not the only concern. If there is blocking weather to our south, say in the Mid-Atlantic, the birds still cannot get to us. However, it has been similarly pleasant in general over much of the east coast. It would not be surprising to see several new species enter the state next week with the typical early May migrants arriving in the last week of April.

When migration starts to get moderate to heavy, we will definitely be posting radar images from various websites so we can all track their progress together.

Photos © Scott Kruitbosch.

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