the marsh wren (cistothorus palustris) is a small north american songbird of the wren family .
it is sometimes called long-billed marsh wren to distinguish it from the sedge wren , also known as short-billed marsh wren .
dults have brown upperparts with a light brown belly and flanks and a white throat and breast .
the back is black with white stripes .
they have a dark cap with a white line over the eyes and a short thin bill .
the male's song is a loud gurgle used to declare ownership of territory; western males have a more varied repertoire .
their breeding habitat is marshes with tall vegetation such as cattails across north america .
in the western united states , some birds are permanent residents .
other birds migrate to marshes and salt marshes in the southern united states and mexico .
these birds forage actively in vegetation , sometimes flying up to catch insects in flight .
they mainly eat insects , also spiders and snails .
the nest is an oval lump attached to marsh vegetation , entered from the side .
the clutch is normally four to six eggs , though the number can range from three to ten .
the male builds many unused nests in his territory .
he may puncture the eggs and fatally peck the nestlings of other birds nesting nearby , including his own species (even his own offspring) and red-winged blackbirds , yellow-headed blackbirds , and least bitterns .
this bird is still common , although its numbers have declined with the loss of suitable wetland habitat .
wholesale draining of marshes will lead to local extinction .
still , this species is widespread enough not to qualify as threatened according to the iucn .
