Photography of Birds – Set # 260
Set # 260
The tan and white morphs of White-throated Sparrows use different reproductive strategies. Tan males invest in parental care and guard their mates from others searching for extra pair copulations (EPCs). White males invest in securing additional mates and EPCs through song advertisement and intruding into neighboring territory. Female morphs have similar differences, where tan females invest in parental care and white females solicit EPCs and engage in brood parasitism, leaving their eggs in another’s nest to be raised and fed. Mating with the opposite morphs and using alternative reproductive strategies helps maintain competitive equilibrium.
Song Sparrows forage on the ground, in shrubs or in very shallow water. They mainly eat insects and seeds. Birds in salt marshes may also eat small crustaceans. They nest either in a sheltered location on the ground or in trees or shrubs. Song sparrows with areas of shrub cover in their territory, away from the intertidal coastline, have greater over-winter survival, as well higher reproductive success.
© HJ Ruiz – Avian101