Wednesday, April 27, 2011

Great-tailed Grackle Expansion

Great-tailed Grackle photographed by me at Farmington Bay, Davis Co., Utah
I just read Larry's post at 10,000 Birds about his noticing Great-tailed Grackle expansion into Northern California.  The first thing I thought was, "Well, if it really is happening, eBird maps will probably show it!"  I discovered that Larry's anecdotal evidence is indeed correct.  Watch the animated maps below and you can see that Great-tailed Grackle presence in Northern California is getting stronger.  Not just there either.  Other locations along the traditional frontier of G-T Grackles have also been reporting more of them and their range does seem to be expanding most notably into Oregon, Idaho, Iowa and the Dakotas.  G-T Grackle expansion doesn't look anything like the rapid range growth of the Eurasian Collared-Dove, but it does appear to be expanding.  The only caveat to eBird data is that eBird use is also expanding and could slightly skew the results favoring expansion, but I'm fairly confident that that influence is minimal in this case.

I'm in Arizona as I type this and Great-tailed Grackles are abundant here I've seen dozens just on my way from the airport and a couple on the hotel grounds.  In Idaho it was special to see them, and it still kind of special too see them in northern Utah.

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Great-tailed Grackle Expansion Map using eBird


  1. Way cool. I hope eBird makes maps like these easier to do in the future. It would be fun to visualize all sorts of stuff over time. Also interesting is watching the gray boxes fill in up in Canada as more people submit sightings up there.

  2. @Drew - eBird's heat maps showing bird range and migration are pretty cool, but it is also fun to see maps animated over time periods like I have done here a few times at Birding is Fun! Using "Paint" and is fairly simple, but it does take some time, and I'd love to see the process automated and easier to do, but I'll keep doing it for now when I am curious.

  3. Another cool thing about this animated eBird map is that is shows the increasing strength of bird reporting across most of Mexico. That is exciting stuff!

  4. Wow, you are amazing with all the ways you use eBird data. I have never played with their automated range maps. Good job! I am surprised to see them headed your way! Nice photo of a noisy bird!

  5. @Kathiesbirds - What can I say? I really love eBird. Unfortunately eBird doesn't have "automated" or animated range maps based on time lines yet. Their heat maps are really cool showing migration. You're right about Grackles. In AZ they are often regarded as a trash bird. When they are fewer and further between, their value to birders goes way up!

  6. I saw one while visiting East Park Reservoir, located directly west of Maxwell, California, about an hour drive northwest of Sacramento.