Reproductive biology

All bush-shrikes appear to be monogamous and territorial. The most remarkable aspects of courtship behavior are dueting, mainly found in Laniarius; the "puffback" displays of Dryoscopus; and the flight songs of Tchagra. Courtship feeding is known in the gray-headed bush-shrike; it may occur in the brubru. Nests, built in trees or bushes, are tidy cups made up of fine rootlets, twigs, and grass. Some species like to incorporate spider web, but the medal of originality goes to the marsh tchagra, which often decorates its nest with snake skin. A few nests, like those built by the rosy-patched shrike, are flimsy, almost transparent, and recall those of

A loggerhead shrike (Lanius ludovicianus) has its lizard prey impaled on a barbed wire fence in California. Shrikes may stash their prey by impaling it on fences or thorned branches. (Photo by Maslowski. Photo Researchers, Inc. Reproduced by permission.)

doves. Bush-shrikes lay few eggs, most often only two or three. The breeding season appears to be favored by the start of a rainy season.

Helmet-shrikes are cooperative breeders, with a dominant breeding pair assisted by helpers. The nest is a compact cup, generally built on a horizontal branch, often made of bark and decorated with spider web. Prionops lay two to five eggs, often four. The breeding biology of five of seven Prionops helmet-shrike species remains virtually unknown.

Cooperative breeding also occurs in true shrikes, in the two species of Corvinella, and in at least one species of African Lanius, the gray-backed fiscal. Lanius nests are of the classical cup-shaped type, generally well structured, but not always neatly made. Eggs number between three and eight; clutch-size varies with latitude, both within the genus and within populations of the same species. The African Lanius lay generally few eggs, for instance, apparently never more than three in Sousa's shrike (L. souzae). However, in Alaska the modal clutch-size of the northern shrike is eight eggs. Young Lanius stay in the nest for two to three weeks, depending on the species, weather conditions, and availability of food.

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