Birds of the Week # 13
American Goldfinch (Male non breeding)
American Goldfinch (Male, breeding)
The American Goldfinch flies in a distinctive undulating pattern, creating a wave-shaped path. This normally consists of a series of wing beats to lift the bird, then folding in the wings and gliding in an arc before repeating the pattern. Birds often vocalize during the flapping phase of the pattern and then go silent during the coasting phase. The call made during flight is “per-twee-twee-twee”, or “ti-di-di-di”, punctuated by the silent periods. The American goldfinch communicates with several distinct vocalizations, including one that sounds like “po-ta-to-chip” to the listener. The American goldfinch does not act aggressively toward predators within its territory; its only reaction is alarm calling. Predators include snakes, weasels, squirrels, and blue jays, which may destroy eggs or kill young, and hawks and cats, which pose a threat to both young and adults. The oldest known American goldfinch was 10 years and 5 months old.
Blue Grosbeak (F)
The male Blue Grosbeak is deep blue, with both black and brown on its wings. The female is mostly brown. Both sexes are distinguished by their large, deep bill and double wing bars. These features, as well as the grosbeak’s relatively larger size, distinguish this species from the indigo bunting. Length can range from 14 to 19 cm (5.5 to 7.5 in) and wingspan is from 26 to 29 cm (10 to 11 in). Body mass is typically from 26 to 31.5 g (0.92 to 1.11 oz).
Eastern Bluebird (M)
Eastern Bluebirds tend to live in open country around trees, but with little understory and sparse ground cover. Original habitats probably included open, frequently burned pine savannas, beaver ponds, mature but open woods, and forest openings. Today, they are most common along pastures, agricultural fields, suburban parks, backyards, and even golf courses. Populations also occur across eastern North America and south as far as Nicaragua. Birds that live farther north and in the west of the range tend to lay more eggs than eastern and southern birds.
House Finch (Male)
House Finch (M) + Juveniles
The House Finch are mainly permanent residents throughout their range; some northern and eastern birds migrate south. Their breeding habitat is urban and suburban areas across North America, as well as various semi-open areas in the west from southern Canada to the Mexican state of Oaxaca; the population in central Chiapas may be descended from escaped cagebirds. Analyses of nest records from House Finches in California spanning more than a century found that egg‐laying occurred significantly earlier in warmer springs. Originally only a resident of Mexico and the southwestern United States, they were introduced to eastern North America in the 1940s. The birds were sold illegally in New York City as “Hollywood Finches”, a marketing artifice. To avoid prosecution under the Migratory Bird Treaty Act of 1918, vendors and owners released the birds. They have since become naturalized; in largely unforested land across the eastern U.S., they have displaced the native purple finch and even the non-native house sparrow. In 1870, or before, they were introduced to Hawaii and are now abundant on all its major islands.
© HJ Ruiz – Avian101Amer