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Posts Tagged ‘California Scrub-Jay’

My wife, daughter and I were in Berkeley, CA this weekend visiting my mom and some friends. One morning, while we were having breakfast and watching the visitor to the bird feeders hanging not far from the floor-to-ceiling windows, we witnessed a pretty dramatic event.

PUFI

A female or juvenile Purple Finch.

As we eat our breakfast, a group of three or four Purple Finches were enjoying their’s. Suddenly, a California Scrub-Jay made an ambush attach on the feeder! It flew in through the branches of the Incense Cedar, and startled the finches into a bit of a panic. One of the Purple Finches (either a female of juvenile bird) made a very bad decision, and flew directly away from the incoming jay which meant it crashed into the big windows right in front of us. The jay flew past the feeder, not stopping at all, and landed on a table near the big windows. It seemed from watching the flight of the jay, that landing on the table had been its plan. The finch was on the deck, stunned by the impact with the window. The jay looked down, watched the finch for a moment to assess its condition, and then jumped down, grabbed the adult finch in its beak and flew away toward a large tree that we are pretty sure this bird and its mate have a nest in! That’s right, as if it was pretending to be one of the small hawks or falcons, the jay picked up the stunned Purple Finch and flew off with it!

CASJ

California Scrub-Jay

This whole event only took a total of about one minute, but it got us all talking and thinking a fair bit about what we had just seen. First off, What a sight to see! All of us around our breakfast table were pretty surprised, impressed, and a few were taken aback at seeing a predator prey interaction at such close range. Secondly, I have never seen a California Scrub Jay prey on an adult songbird, before! I looked it up, and while there are reports of similar behaviors, they are not common. Thirdly, was driving a finch into the window the jay’s plan? The jay seemed like it was aware of the window, as its movements never put it in any danger of colliding itself. The finch was either unaware of the window, or was so frightened by the jay’s sudden attack that it forgot about it. So, did the jay basically hunt the Purple Finch using a window? Jays, members of the corvid family along with ravens, crows, magpies, and others, are highly intelligent and have been observed using tools in a range of settings. So, using a tool such as a known window location to incapacitate prey certainly seems possible.

Regardless of whether or not the window was used as a hunting tool, or if the jay just got lucky, this was a pretty impressive sight to see. And those baby jays had a very big breakfast of their own that morning!

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The American Ornithologists Union (AOU) is, among other things, the arbiter of avian taxonomy in Middle and North America. They are the organization that rules on whether a species should be split in two, or if two species should be lumped together. They are the organization that rules that Loons are no longer the most basal group of North American birds, but that they group that contains ducks, geese and swans holds that honor. The AOU releases all these decisions in the form of annual Supplements to the official AOU Checklist (which is a complete list of all bird species and subspecies listed in taxonomic order).

A lot of science has to be done before the AOU makes any of these ruling, and these ruling are subject to change as more science is done, but at any given time, the current AOU Checklist represents the best available knowledge on how many species of birds there are and on how they are  all related to one another.

Well, the AOU just released their most recent Checklist Supplement and it has, among the many updates and changes, an interesting change for California. Since that is where I live, I am particularly interested in this one. It concerns a common member of the corvid family that anyone who has spent any time outside has seen. The Western Scrub-Jay (Aphelocoma californica).

This species has actually already had an interesting history in the taxonomy world. Before 1995, there was one species recognized as a Scrub Jay (Aphelocoma coerulescen). This species was found across the western USA and also in Florida. In 1995, the AOU split the Scrub Jay into three distinct species. They were the Florida Scrub-Jay, which retained the original scientific name (Aphelocoma coerulescens), recognizing the Florida population as genetically distinct; the Island Scrub-Jay (Aphelocoma insularis) recognizing the population found on the Channel Islands off the coast of southern California as genetically distinct; and the Western Scrub-Jay (Aphelocoma californica) which included all the remaining populations in the western continental USA.

California Scrub-Jay - Frank Lang

California Scrub-Jay (Photo credit: Frank Lang)

Now, in the most recent AOU Checklist Supplement, the Western Scrub-Jay has been split again. We now have the California Scrub-Jay (Aphelocoma californica) recognizing that the population along the Pacific Coast is actually genetically distinct from the Woodhouse’s Scrub-Jay (Aphelocoma woodhouseii) found in the inter-mountain west.

Woodhouse's Scrub-Jay - Robert Mortensen

Woodhouse’s Srcub-Jay (Photo credit: Robert Mortensen)

In addition to the genetic distinctions, these two new Jay species also have behavioral and morphological differences. The California Scrub-Jay is darker in color, generally lives in Oak woodlands, and eats a range of seeds including a lot of acorns and so has a heavier bill. In contrast, Woodhouse’s Scrub-Jay is lighter in color, generally lives in the Great Basin pinon-juniper scrublands, and correspondingly eat a great deal of pinon pine nuts and juniper berries and so have a slimmer bill.

So, update your life lists, start getting used to using the new four-letter codes of CSJA (now standing for California Scrub-Jay) and WSJA (Now standing for Woodhouse’s Scub-Jay, and not Western Scrub-Jay that it used to identify), and enjoy picking apart the finer levels of identification between these two newly recognized species!

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