Thursday, June 21, 2012

on Dickcissels and Blue Grosbeaks

vagrant Dickcissel seen in Farmington, Utah 2011
probably my favorite Blue Grosbeak photo
by "Birding is Fun!" contributor Steve Creek.
Donald the Birder's post this morning here talking about Dickcissels and Blue Grosbeaks in the same vicinity in Ohio got me to thinking. In Utah last year, we had a vagrant Dickcissel and it was also very near a nesting pair of Blue Grosbeaks. It got me to wondering if there were some connection between these birds regarding habitat or diet that may have made these birds migration buddies.

AllAboutBirds.org describes Dickcissels as birds of the prairie grasslands and Blue Grosbeaks as birds of the open woodland or forest edge. I suppose there are habitats of grassland and forest edges near each other. Their diets of seeds and insects appear to be pretty close to the same. Let's take a look at some eBird sightings maps and see what we can learn...(see maps below)

These eBird sightings maps reveal that Dickcissels and Blue Grosbeaks do seem to share their winter range in Central America and around the Gulf of Mexico. It appears that Dickcissels in winter tend toward more vagrancy than Blue Grosbeaks. Dickcissels must be found in higher concentrations in their Central America wintering grounds due to the sparse amount of sightings, or they may be harder to find in winter for some reason. AllAboutBirds.org states that winter roosts of Dickcissels may number in the millions of birds.

All kinds of interesting stuff here, but what about my original curiosity about why Donald and I both saw the two species together? Is there some mysterious connection between the two species. Ah, it was probably just coincidence.

Blue Grosbeak Dickcissel
Summer - concentrations in the southern states, in the southwest, and in southern Mexico
Summer - largest concentration in the prairie lands of the midwest and along the Mississippi River corridor
Winter
Winter

7 comments:

  1. I have reported on ebird my only blue grosbeak of the year so far and the Dicksissals are definitely abundant there: Ok state Cross county course just north of campus.

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  2. I think that it is more than just coincidence, as looking back, everywhere that I have seen Dickcissels, I have also seen Blue Grosbeaks nearby. However, I have seen Blue Grosbeaks in habitats that I would not associate with Dickcissels. Blue Grosbeaks are more adaptable than Dickcissels when it comes to habitat. Just wish I had more time to study such things - good stuff.

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    1. My first Blue Grosbeak was in some open woodland areas in Prescott, Arizona. Since then, I have only seen them a couple times in open fields with mid-size bushes nearby.

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  3. Sounds like there's an overlap with Blue Grosbeaks into Dickcissel territory, both regarding range and local demography, but you won't find Dickcissel's everywhere you'll find Blue Grosbeaks (in AZ, for example).

    Interesting nonetheless. Nice work Robert! The folks at Cornell would be lucky to have ya.

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    1. When it comes to bird science, I am pretty superficial, meaning I only enjoy the surface level of science. You know, the pretty graphs, pictures, and maps. I get lost when it comes to all the work behind the pretty bottom line from the studies.

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  4. these are two life birds for me this year. Nice post Robert

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  5. What a treat to see either species. I have seen the blue grosbeak several times in AZ but only got a passing glimpse of a Dickcissel on a BwBTC outing in CT last year near Wilton, CT! I would love to see one again and in breeding plumage this time, LOL!

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