Tuesday, July 3, 2012

Mexican Jay vs. Western Scrub-Jay

As I converted my life list to eBird, I lost several species. One was the Mexican Jay I saw in Oaxaca. According to eBird, Mexican Jays are not found in Oaxaca. So it was with enthusiasm that I followed my brother during our recent road-trip to New Mexico. He told me he knew where to look for them and how to separate them from Western Scrub-Jays. According to the field guides, as you can see from these photos, Mexican Jays (above) have gray throats and cobalt-blue upperparts (this last color is well-illustrated in the National Geographic Guide), while scrub-jays (below) are darker blue above and have white throats.

"The way you tell them apart," said my brother, "is that Mexican Jays are found in higher elevation, oak forests and are seen in noisy flocks. Scrub-Jays are usually alone or in pairs and are more often silent."

The Mexican Jay is found from the southern southwest United States to central Mexico. This jay is highly social, flocking in groups of five to 25 individuals. These flocks have a complex organization. Several females may breed simultaneously and monogramously. The young, however, are fed by most flock members. Flocks tend to be sedentary and non-miratory. Individuals within the flock may live past 20 years, either in its birth territory or in an adjacent one (McCormack and Brown 2008). My brother knew just where to look.

Compared to Mexican Jays, Western Scrub-Jays are found over a wider range across the western United States and central Mexico. They also enjoy a wider habitat range, including suburban cities. Scrub-Jays tend to frequent lower and drier areas than Mexican Jays. Western Scrub-Jays are less social than Mexican Jays or Florida Scrub-Jays (Curry et al. 2002).

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