Species of the Month

November’s article written by Brian Pomfret, Master Bird Bander at Ruthven Park National Historic Site

(Originally published in October 2023)

As October departs and the year continues to inexorably draw to a close, many of the long distance, neotropical migrants, such as warblers, flycatchers, and vireos, have left the northern part of their ranges for the south. October is the month when short distance migrants, birds that breed in the north and overwinter in the southern United States typically, are most evident.

The White-throated Sparrow (Zonotrichia albicollis) is an example of a short distance migrant. Breeding mostly in the deciduous and coniferous forests of Canada from central British Columbia eastwards through to Newfoundland, the White-throated Sparrow overwinters along the Pacific coast and through the central region, eastwards and southwards, of the United States.

The White-throated Sparrow typically weighs between 25 and 30g, is approximately 17cm in length, and has a wingspan of between 20 and 23cm. They are streaky brown above, range from grey to white below, and, as their name reveals, has a white throat.  Individuals have either black and white, or brown and tan striping on their heads, and have two yellow spots – called “lores” – between their eyes.

As it is typical for a black and white striped White-throated Sparrow to pair with a brown and tan striped White-throated Sparrow during nesting, it was thought that the black and white striped individuals were male and the brown and tan striped ones female. Recent research, however, has shown this is not the case. Either gender can have either coloured pattern of stripes. Among males black and white striped females are preferred, while females prefer brown and tan striped males.

White-throated Sparrows are mostly found along forest edges, or in shrubby areas of regrowth following logging or forest fires. They feed on the ground, or in low shrubs, on the seeds of grasses and a variety of other plants, and upon the fruit of grapes (Vitis sp.), sumac (Rhus sp.) and Mountain Ash (Sorbus sp.).

White-throated Sparrows have longish legs, and large feet with long nails. They move along the ground in hops, rather than walking or running, and forage in leaf litter by hopping backwards while scrapping with both feet together, dragging detritus with them. They quickly pounce forward on whatever food stuffs are uncovered.

White-throated Sparrows can not produce the yellow colouration of their lores on their own. They need a diet rich in carotenoids, pigments produced mainly by plants, to provide this colour. The grapes in their diet are a good source of carotenoids.

Nests, made of bark, grasses, and other detritus, are built on the ground. Often they are centered on small, naturally occurring depressions. If the first nest is lost to a ground predator however, the second attempt will typically be high up in a tree. Young White-throated Sparrows leave the nest approximately 10 days after hatching. The fledged young are then fed by the parents for 14 days or so. Typically the White-throated Sparrow can raise two broods during a nesting season.

While most White-throated Sparrows pass through our area of southern Ontario to their overwintering grounds in the United States, an increasing number of them now overwinter here. They are usually found in flocks of various sizes in thickets, overgrown fields, and sheltered backyards.

White-throated Sparrows often frequent bird feeders during migration and while overwintering. They prefer black oil sunflower seeds and millet. Often they feed on the ground on seeds spilled from bird feeders, but will to perch on platform feeders as well.