When does the Black-tailed Grosbeak breed? The breeding season of the black-tailed grosbeak is usually from March to October, but it varies depending on the geographical environment. Generally speaking, the breeding period of grosbeaks is about two months, and the incubation period of grosbeaks is about 15-20 days.
The breeding period of the Black-tailed Grosbeak is from May to July . Soon after arriving at the breeding ground, the male bird begins to sing courtship calls and pair up. The male bird often stands on a branch and sings loudly, and the song is clear and sweet. From early May to mid-May, they begin to build nests on the lateral branches of oak trees, poplar trees, mountainside trees or other trees, 2-7 meters high from the ground.
The nest is cup-shaped or bowl-shaped and is made of grass leaves, grass stems, fibrous roots, twigs and other materials. The outer diameter of the nest is 9-14 cm, the inner diameter is 6-8.5 cm, the height is 8-13 cm, and the depth is 5-8 cm. Each clutch lays 3-7 eggs, mostly 4-5 eggs. The color of the eggs varies greatly, some are beige with light red spots, some are gray or off-white with dark brown spots and stripes, and some are duck egg blue or dark gray with dark brown stripes.
