Measurements
Both Sexes
- Length
- 11.4 in
29 cm - Weight
- 4.2–4.8 oz
120–135 g
Other Names
- Gray-breasted Jay
- Geai du Mexique (French)
- Grajo Azul, Charra Azulosa, Urraca Azulejo, Parajo Azul, Ruín (Spanish)
Cool Facts
- In most populations of the Mexican Jay, young jays have large areas of white or flesh color on the basal half of the bill. It can take more than two years for the bill to turn entirely dark. These light areas on the bill may be asymmetrical and can be used by observers to identify individual jays.
- Mexican Jay groups may number from 5 to 25 individuals, and may contain several active nests within one territory. Only the socially paired group members engage in nest-building, incubation, and brooding. All group members do virtually everything else, including alarm calling, mobbing, and feeding the young. Some jays feed at several nests within the territory, others feed at only one, and still others do not feed any young at all.
- Genetic studies have shown that parentage within a Mexican Jay group is complicated, with most nests containing young sired by different males. Most of the extra-pair young were fathered by males within the group that did not help in nest building and did not appear to be paired.
- In winter, Mexican Jay groups are often followed by Northern Flickers. The flickers pay attention to Mexican Jay alarm calls and are protected from predators by the vigilance of the jays.
- The oldest recorded Mexican Jay was a male, and at least 17 years, 8 months old when he was identified by his band in Arizona in 1987. He had been banded in the same state in 1969.
Habitat
Open Woodland
Found in pine, oak, and juniper woodland.
Food
Omnivore
Acorns, pinyon nuts, arthropods, lizards.
Nesting
Nesting Facts
- Clutch Size
- 1–6 eggs
- Egg Description
- Greenish, with or without dark markings.
- Condition at Hatching
- Naked and helpless.
Nest Description
Nest an open cup of twigs with an inner layer of rootlets, lined with plant fibers. Nest placed in tree.
Nest Placement
Tree
Behavior
Ground Forager
Forages on ground and in trees. Harvests and hides (caches) acorns and other nuts. Holds food under feet to peck at it.
Conservation
Least Concern
There is little information on Mexican Jay population trends. Though populations are restricted, they appear stable. Partners in Flight estimates a global breeding population of 800,000 with 17% living in the U.S., and 83% in Mexico. The species rates a 12 out of 20 on the Continental Concern Score. Mexican Jay is not on the 2016 State of North America's Birds' Watch List.
Credits
- Brown, J. M. 1994. Mexican Jay (Aphelocoma ultramarina). In The Birds of North America, No. 118 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
- Jones, Z. F., and C. E. Bock. 2003. Relationships between Mexican Jays (Aphelocoma ultramarina) and Northern Flickers (Colaptes auratus) in an Arizona oak savanna. Auk 120: 429-432.
- Li, S.-H., and J. L. Brown. 2000. High frequency of extrapair fertilization in a plural breeding bird, the Mexican jay, revealed by DNA microsatellites. Animal Behaviour 60: 867-877.
- North American Bird Conservation Initiative. 2016. The State of North
America’s Birds 2016. Environment and Climate Change Canada: Ottawa, Ontario.
- Partners in Flight. 2012. Species assessment database.
- USGS Patuxent Wildlife Research Center. 2016. Longevity records of North American Birds.