The North American population (nominate ssp.) exhibits extensive geographic variation, with clinal variation: larger birds with shorter appendages in colder climes, darker plumages in more-humid ...

The Cape Sable seaside sparrow isn't nicknamed the “Goldilocks bird” for nothing: In order for this little sparrow to survive, its habitat conditions have to be just right. Though the bird has evolved ...

A true connoisseur of coastal living, MacGillivray's seaside sparrow spends its days munching on tiny crabs, insects and seeds in Atlantic coastal marshes. This little gray-brown bird — one of four ...