Scrub Jays in Eden

One more from Colorado (everything today was too far out on the lake for pictures, I'm afraid).

Western Scrub Jay (Aphelocoma californica), Garden of the Gods, El Paso Co., CO  12/26/13.

This is a Western Scrub Jay, one of six species in the genus Aphelocoma. This species occurs from the West Coast of the US east into the Great Basin all the way to the front range of Colorado, and south into southern Mexico. Another species, the Florida Scrub-Jay (A. coerulescens), is found in central Florida, but only in patches, as most of its range has been fragmented by agriculture. It is listed as a Threatened Species. Another species, the Island Scrub Jay (A. insularis), is endemic to Santa Cruz Island off of southern California. The last US species, the Mexican Jay (A. wollweberi), occurs from mountains near the Mexican border, south into central Mexico. The other two species, Transvolcanic Jay (A. ultramarina) and Unicolored Jay (A. unicolor) occur from central Mexico into Central America.

Like most members of the Corvidae (crows, ravens, magpies, and jays), these birds are quite social, typically traveling in flocks. This genus is of interest to biologists because in some species, these flocks are frequently composed of a mated pair and several offspring from previous years. These offspring actually help feed the nestlings of the mated pair. This system is typically referred to as cooperative breeding. It has not been documented in Western Scrub Jays, but it is well studied in Florida Scrub Jays (imagine, biologists wanting to study critters in sunny Florida!) and has been documented in Mexican Jays in Arizona and Transvolcanic Jays in Oaxaca. Since there is variation between both species and populations within species, they serve as an excellent group to test hypotheses regarding the evolution of this behavior. It appears, at least at present, that cooperative breeding is a response to a geographically limited habitat -- if you probably can't get a territory of your own, you may as well stick around and help your siblings out while you wait.

Of course, social life has other advantages. For instance, more birds around means more eyes out for predators. And in Florida Scrub Jays, Kevin McGowan and Glen Woolfenden were able to document that these birds actively maintain a sentry position, noticing that birds started sentry behavior just as other birds stopped, more often than expected in a random model. (1) This actually appears to be fairly unusual among birds, although Meerkats apparently behave in a similar fashion.

The flip side to being a social bird is one we're all aware of -- many birds would prefer to cheat! Scrub Jays, like many corvids, cache food for later consumption. However, they're not above stealing each other's caches. A number of authors have examined the bird's responses to each other, and Nicola Clayton, et al., reported that Western Scrub Jays will not only move caches if they were observed placing them, but will apparently take into account which individuals were in view at the time. (2) They suggest that this indicates that the birds consider other individual's mental states. This sort of behavior is part of why corvids in general are considered to be among the most intelligent of birds.

It's been hypothesized that consciousness arose in humans as a result of social interactions within groups. Here we have a group of birds that not only live in groups, but show sophisticated social behaviors. We already know that some species (Gorillas and Chimpanzees, for example) show some signs of what we would call consciousness. It seems to me that an opportunity to test this hypothesis of consciousness is sitting right in front of some promising psychology student - in part thanks to the Scrub Jays that send their calls echoing off the rocks at Garden of the Gods.


(1) Kevin J. McGowan, Glen E. Woolfenden, A sentinel system in the Florida scrub jay, Animal Behaviour, Volume 37, Part 6, June 1989, Pages 1000-1006, ISSN 0003-3472, http://dx.doi.org/10.1016/0003-3472(89)90144-9.
(http://www.sciencedirect.com/science/article/pii/0003347289901449)
  

(2) Nicola S Clayton, Joanna M Dally, and Nathan J Emery.
Social cognition by food-caching corvids. The western scrub-jay as a natural psychologist,

Phil. Trans. R. Soc. B April 29, 2007 362 1480 507-522; doi:10.1098/rstb.2006.1992 1471-2970