Dwarf jay  (Cyanolyca nana)

The dwarf jay is classified as Vulnerable (VU) on the IUCN Red List (1).

The small, slender dwarf jay (Cyanolyca nana) is an attractive bird, with greyish-blue plumage and a distinct black ‘face mask’ (4). A whitish ‘eyebrow’ stripe extends above each reddish-brown eye and the bill is black (4) (5). The throat is whitish and is separated from the rest of the underparts by a darker line. Juvenile dwarf jays have a much smaller, less defined throat patch, which blends gradually into the rest of the plumage (4).

The dwarf jay often appears in flocks with Steller’s jay (Cyanocitta stelleri) but the dwarf jay can be easily distinguished by its smaller size, lighter plumage and the lack of a prominent crest of feathers on top of the head (6).

Compared with other jay species, the dwarf jay has a fairly small vocal repertoire, with just two main, nasal-sounding calls, either a “shree-up” in units of two or three or a single cry of “shiev-a shiev-a” (2).

The dwarf jay has a small and fragmented distribution in south-eastern Mexico. It was once thought to be restricted to southern Veracruz and northern Oaxaca, but recent surveys have also found small numbers of the dwarf jay in northern Hidalgo, eastern Querétaro and central Veracruz (7).

The dwarf jay inhabits humid pine, oak and fir forest (8), at elevations between 1,400 and 3,200 metres (7).

Thought to be a largely insectivorous bird, the dwarf jay is known to feed on weevils, bark beetles, crane flies and wasps, but it may also consume some plant fibre (8).

The dwarf jay forages in groups containing between four and ten individuals, often in a flock with other bird species. It is an agile bird and may be seen hanging upside down as it searches amongst vegetation for food.  It also investigates tree stumps, searches under peeling bark, and will break open plant galls in search of hidden larvae, as well as pursuing slow flying insects (8).

In March, the male dwarf jay presents food to the female as part of the courtship ritual. Once a pair has formed, a tightly woven cup-shaped nest of mosses and lichen, lined with pine needles, is usually constructed in an oak tree at a height of about seven metres. The female dwarf jay typically lays two to three eggs, which are a pale greenish-blue, marked with olive spots. The eggs are incubated for around 20 days by the female alone, but the newborn chicks are fed by both parents (6).

It is thought that the grey-barred wren (Campylorhynchus megalopterus) and Steller’s jay (Cyanocitta stelleri) may prey on the eggs and chicks of the dwarf jay, and a sharp-shinned hawk (Accipiter striatus) has been observed attacking an adult dwarf jay (6).

The greatest threat to the dwarf jay is habitat loss, due to human activities such as logging, agriculture, firewood gathering, road construction and cattle grazing. The dwarf jay is particularly sensitive to human presence, and any disturbance typically leads to the dwarf jay abandoning its nest (7) (9).

Climate change poses a long-term threat to this species, as it is likely to alter the dwarf jay's preferred habitat (7). For example, it has been predicted that climate change will result in tropical forest in southern Mexico being replaced by savanna (10).

This endangered species is not currently known to be the focus of any specific conservation action. It has been recorded in Benito Juárez National Park, but this is believed to offer the dwarf jay little protection in practice (7).

Effective protection of this National Park has been recommended, as has the protection of other sites where this attractive bird has recently been recorded (7).

Learn more about bird conservation:

• BirdLife International:
  http://www.birdlife.org/

Find out more about conservation in Mexico:

• The Nature Conservancy:
  http://www.nature.org/ourinitiatives/regions/northamerica/mexico