White-Throated Sparrow

The white-throated sparrow belongs to the American sparrow family and is found all over the coniferous forests of North America. They get their names from their bright white throats bordered by a dark malar stripe.

These beautiful singing birds are also called as Canadian sparrows as they are found all over Canada. They are polymorphic and come in two colors or morphs – the white-striped and the tan-striped, which makes them even more distinctive and special.

White Throated Sparrow Scientific Classification

Kingdom	Animalia
Phylum	Chordata
Class	Aves
Order	Passeriformes
Suborder	Passeri
Superfamily	Passeroidea
Family	Emberizidae
Genus	Zonotrichia
Scientific Name	Zonotrichia Albicollis

White Throated Sparrow Quick Information

Other Popular Names	Bruant a Gorge Blanche (French), Sabanero de Garganta Blanca (Spanish), White Throat
Size	Both sexes –  Length: 6-7 inches; Wingspan – 8-9 inches; Relative Size- Slightly bigger and heavier than a song sparrow
Weight	0.8-1.1 oz
Color	Two color forms – white striped (crowned) and tan striped (crowned) that are genetically determinedWhite-Striped– Brown and grey plumage with an attractive head pattern, throat is bright white, yellow patch between eyes and beak   Tan-Striped-Less boldly patterned, face is buff with brown hues
Distribution	Breeding – They breed in summer in the range extending from Northwestern Canada to Minnesota, the Great Lakes region, and New EnglandWinter – They spend their winters in the Eastern regions of the United States, the area spans from New England to northern Mexico
Habitat	Live in coniferous and mixed forests; prefer forests with openings of vegetation like beaver ponds and open bogs. Also found in artificial greenery like parks and gardens as well as shrubs and cattail marshes. Second growth after fire or logging is highly preferred for breeding.
Sound	Call – A shrill “pink”-similar to a white-crowned but with a high-pitched voice. Husky chatter of flocks of birds.Song – Thin whistle containing 1 or 2 single notes, following this are 3 or 4 long notes that have a different voice pitch and are tripled   Flight notes – slurred and lisping “tseet” with a harsh chink. Dusk Vocalizations – A much sharper and shriller whistle that consists of a single “twit” uttered till nightfall
Clutch Size	1 to 6 eggs, one or two broods per season
Incubation Period	11 to 14 days
Lifespan	9.6-14.9 years
Diet	Fall and winter – Small berries and seeds Summer – Eats more of insects; fruits and greens too
Predators	Enemies during daytime – Marsh Hawk, Sharp-shinned or slate-colored hawk, little Sparrow Hawk- also known as American kestrelPredators- Least weasel, raccoons, domestic cats, great horned owls, Cooper’s hawks and American crows
IUCN Conservation Status	Least Concern  with a stable population trend

Behavior

White-throated sparrows hop on the ground instead of walking and running. They dig through leaf litters and dense shrubbery to uncover and catch insects. During summer, they prefer foraging low trees. These small birds can fly rapidly and make short trips between nearby branches.

These passerines are a model for differing behavioral characteristics due to chromosomal changes in the two morphs present. The white-striped birds (both males and females) sing more and exhibit more aggression that their tan-striped counterparts. On the other hand, the tan-striped ones are more caring parents and the males of this category guard their mates as well. This difference in behavior is attributed to a special chromosome called as the ZAL 2 M chromosomes and is a milestone in the genetics of social psychology of these birds.

Migration

These birds are migratory and winters in the southern and eastern parts of the United States. A really small number of sparrows migrate to West Oregon, where they overwinter in the Columbia and Klamath River Basins.

However, the birds found in the Atlantic provinces of Canada do not migrate at all. Some of them have been observed to be vagrants to Western Europe as well. These small birds are one of the most common indigenous birds in North America during the winter even though small raptors like hawks and owls prey upon them extensively.

Mating and Reproduction

As the breeding season draws near, the sparrows start singing from the trees. The males engage in singing bouts to attract a female and become very territorial during this time, driving other males away.

However, this aggressiveness reduces as the breeding season draws to a close. Though these birds are generally monogamous, they may sometimes change partners.

These passerines like to construct their nests on the ground or in small shrubs and trees in semi-open clearings in the forests. The location of their nests is selected in such a way so as to ensure the chicks’ safety and security. They are always situated near logs, stumps or trees that serve as obstacles from where they can perch and keep a look out for predators. If a predator robs their nest on the ground, they attempt to build a second nest that is situated at a higher level from the ground.

Their nest is cup-shaped and is built by the female over a span of 4 to 6 days. These small birds make use of grasses, twigs and rootlets to build their nests and they are often covered with hair that serves as a soft lining for the chicks.

Life Cycle

After the nest building process is over, the female sparrow lays 4 to 6 eggs. The eggs are light blue or greenish in color and are covered with dark markings in the peripheries. She then incubates the eggs for 11 to 14 days.

The newborn chicks are altricial, meaning that they don’t have feathers and are almost naked – being covered only with brown down feathers. The newborn babies are totally dependent on both their parents who care for them by fulfilling all their needs.

The chicks fledge after 7 to 12 days but need 2 or 3 days more to be able to fly unhindered. The juveniles are ready to breed after they are a year old.

Adaptations

• Passerines like the white-throated sparrow are equipped with feet that consist of three toes facing towards the front and one toe facing backward strengthened with interlocking tendons that help them in perching.
• The white and tan colored sparrows generally mate with members having the opposite coloration. This ensures that an equal number of babies are produced for each sex and color thus, ensuring the stability of both color morphs in the bird population.
• These birds are able to scratch by using both legs at the same time helping them to search for food. This quality is unique to passerines and is not found in other birds.

Interesting Facts

• White-throated sparrows are nocturnal migrants and commence their flights at sunset. According to some researchers, they probably use star patterns for navigation.
• These birds only feed animal matter that mainly includes insects to their babies.
• Their song is also described by some birders as “Poor Sam Peabody, Peabody, Peabody”, in addition to “Pure Sweet Canada, Canada, Canada”
• Males of both color morphs seek white-striped females and females of both colors seek tan-striped males.
• They come together in flocks during winter and establish hierarchies or pecking orders.
• These birds are more common in urban areas than most other species of sparrows.
• Hybrids are produced when the white-throated sparrow and the dark-eyed junco mate occasionally. The most interesting aspect of this is that these two birds neither look alike nor are they closely related. They give birth to dull, grayish sparrows with white feathers on their tails.
• Johann Friedrich Gmelin, a German naturalist was the first researcher to give a description of this bird way back in 1789.

References:

1. https://en.wikipedia.org/wiki/White-throated_sparrow
2. https://www.iucnredlist.org/species/64131/12747877
3. https://www.nationalgeographic.com/animals/birds/facts/white-throated-sparrow
4. http://animaldiversity.org/accounts/ Zonotrichia_albicollis/
5. http://www.biokids.umich.edu/critters/ Zonotrichia_albicollis/