Dear Journey North,
Today I begin my reports about spring songbird migration, although for much of the country it hasn't felt much like spring! (That includes here in Tennessee, where it is snowing—with more snow expected tomorrow!) Nonetheless, there are signs spring is approaching.
Signs of Spring
For the past week I have been hearing the first robins, cardinals, and Song sparrows singing, which is about a month later than I heard them last year. The bluebirds are pairing up and are busily checking out nest sites. Best of all, it won't be long before migrants start arriving from their wintering grounds in the tropics. In fact, the earliest migrants that arrive here, Tree Swallows, arrived last week, and are busily staking their claim to nest boxes in the area! Before you know it, the country will be overrun with warblers, vireos, tanagers, thrushes, and other migrants coming up from their tropical wintering grounds. Before that happens, we have some work to do!
Weather and Migration
Songbird migration is very dependent on weather conditions, so in order to understand when and where songbird migration may occur, you need to know how to read a weather map. Each week, I will be showing you the map for that week's weather, and help you predict who might see lots of birds arriving. Then the next week, I will report on bird sightings from all over the country and see if the predictions were correct. Let's get started with my tutorial on how to read a weather map and how weather affects bird migration!
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- You can see that there are several high-pressure areas bringing north winds to the eastern half of the country. If spring migration were underway, many birds would be forced to land because of headwinds, and people would see lots of birds around.
- On the backside of those highs, winds are from the south, which means that western migrants could make a lot of progress north. However, look closely and you'll see a low- pressure area over the southwestern US, which could bring some rainy conditions to that area. So, while migrants that might already be here could do a lot of flying, migrants arriving from the tropics might have to land for a day or two.
It will still be another couple of weeks before migration gets underway, so that will give you a chance to work on your weather skills!
Take care.
David Aborn
North Chickamauga Creek Conservancy
Chattanooga, TN
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