Thursday, March 27, 2014

How to watch migration

Golden-winged Warbler, Minnesota, 2010
Spring 2010 I got hired to travel all over Minnesota and Wisconsin in search of Golden-winged Warblers. That job is how I originally got introduced to eBird.  Every day, starting in April, I checked the Golden-wing map to see if they had arrived in Wisconsin yet. Finals were the last week in April and my crew was set to jump in the vans and head to Wisconsin as soon we finished our exams. We were just waiting for eBird to show us if the birds had arrived, and arrive they did!

Checking eBird every day and watching eagerly for those points to get farther and farther north got me addicted to checking eBird and diving into the immense amount of data eBird has about bird migration.

eBird is a treasure trove of information. Its a great way to learn about a new place and it provides us really neat ways to look at how migration varies from year to year. It also provides you near real-time data so you can see what is going on with migration RIGHT NOW! This makes it an addictive tool, especially in the spring when I am chomping at the bit for all the birds to come back. 

How do you do this? It's quite easy, go over to and click on 'explore data', then click on 'range and point maps'. In the upper left hand corner type in the species of your choice. Right now it's mid march, and the Purple Martins are starting to make their way north, so lets take a look at these signs of spring.

So the first time you enter in Purple Martin it's going to show you everywhere a purple martin has every been recorded. Crazy, and a bit overwhelming.

Next to the species slot is one labeled 'Date'. Checking these maps is where migration becomes watchable. Click on the date drop down and select 'current year'. Choosing this option limits the map to just the areas where Purple Martins have been observed during the current calendar year.

So check it out. I'm currently in NW Arkansas and I've been hearing reports of martins on the list serve for awhile. It looks like Purple Martins are just starting to push north of Arkansas. Since the Midwest has been getting regularly hit with snow over the past few weeks this is probably a wise choice on the part of the birds, though it looks like spring might finally be arriving!

By checking out maps like these for a wide variety of species you can watch migration happen and if you check back every day or every few days you can see the line of purple slowly move north and can better expect what might be around your favorite patch.

What is also fun to look at is how the current 'range' of a species compares to other years.

So head back up to the date drop down and change two things. Instead of current year click on 'last 10 years' and change the month range to just march (so March to March, it's weird, i know).

You should see something like this: Which presents a different picture.

Part of the difference between these two images could be because March isn't over yet, and chances are Purple Martins will make it farther north before April 1st. It might also show the difference between this year and the last, so check back at the map at the end of the month.

The big message here is bird distributions vary year to year. By looking at the 10 year image you can see the farther north areas are lighter purple, indicating less sightings. So not every year are Purple Martins back in Minnesota or northern Ohio by the end of March, but some years they are. Boone's post back at the end of February talked about how spring migration can be treacherous for birds, and how they delay their progress north until conditions improve. Birds are in a race against time, trying to make the most of the good summer weather and be the first ones back on the breeding ground. Some years this pans out and they make it farther north by the end of March. Other years, like 2014, winter is sticking around for awhile, and these birds will either hang out farther south and wait or deal with the chilly weather farther north.

Try out other species and see what is headed your way soon! You might be surprised what is hanging out just a few miles south of you waiting for the weather to break. And of course put your own sightings into eBird and help give everyone north of you some hope as well. But most of all get out there and see what is showing up, many species will keep moving north no matter what the weather and you might be surprised what is already around. Spring is coming and the birds right along with it!

- Auriel

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