Each Spring the woodlands of America resound to the birdsong of returning visitors. Warblers – fifty three species of them all in all – arrive and right now is the best time to see them as they migrate. Their arrival heralds a dazzling dash of colour as the greenness of American forests is peppered as if with the ravishing hues of thousands of tiny precious stones. Here are some of the returnees announcing the spring in their unique way. It must be said that they usually seem to be a little happier than the disgruntled looking Yellow-rumped Warbler above.
The male Chestnut-sided warbler (above) cannot be mistaken. They have dark-streaked grey backs with white faces and black eyestripes. This is topped off with an olive crown. They breed in the eastern North America and the south of Canada.
Like all New World Warblers, the Hooded Warbler (above) winters in Central America, only to return to the United States to nest every spring. They feed on insects which they find in low vegetation or, rather more spectacularly, they will catch their meals by hawking. This is when they watch for their prey from a perch and then fly after it and snatch it from the air in their beak. The Hooded Warbler is often the victim of brood parisitism by the Brown-headed Cowbird.
Townsend’s Warbler is named after the US ornithologist John Kirk Townsend who discovered the bird in 1833 on an expedition that went across the Rocky Mountains and on to the Pacific Ocean. They make shallow cups for nests and usually lay four or five eggs. Where ranges overlap they breed with the very similar Hermit Warbler.
The Yellow Warbler breeds all over North America and in the summer the males of this group are the yellowest of all warblers (although with some washed out streaks on their breast), as you can see from the picture above. This bird is also parasitized by the cowbird but they will often smother the egg with new nesting material or abandon the nest altogether. Occasionally though, they will raise the cowbird with its own brood as, notably, the cowbird nestling will not attempt to kill the young of its host.
With the black stripe over his eyes the Magnolia variety looks like the Dick Turpin of the New World Warblers. It breeds in coniferous woodland and, like most warblers, lays its egg in a rather flimsy cup of a nest. They will also feed on spiders and other insects and will even take berries in inclement weather when their natural prey stay hidden.
This beauty is the Prothonotary Warbler, so called because of the resemblance between it and officials of the Roman Catholic Church who bore the name originally and who wore golden vestments. Unfortunately these birds are declining in numbers due to loss of habitat and also competition from the House Wren.
Many of the warblers here have a consistent problem with nest parisitism and you may not think that is too much of a problem. However, when you look at the difference in size between this Wilson's Warbler and the cowbird nestling that it has unwittingly raised as its own the issue becomes rather more transparent. The picture below gives you an even better idea about just how small the Wilson's really is.
The Blue-winged Warbler (above) is fairly common and breads in eastern North America where its range is extending northwards. A bird was once found in Ireland but it usually stays put in the Americas. It nests in a very low bush or even on the ground and can lay up to seven eggs in a single clutch.
This cheeky looking chap is the Cape May Warbler which breeds in virtually all of Canada and in to New England and the Great Lakes. It winters in the West Indies but when in its breeding habitat at the edge of coniferous forest it likes to nest in the thick foliage at the base of its preferred tree, the Black Spruce. It can lay up to a magnificent nine eggs.
The Yellow-throated Warbler loves to live in coniferous forests but can also be found in swamps. Although they eat insects and can catch them using a hovering technique they will also eat a large amount of berries and will consume nectar outside of their breeding time. They will hide their nest with either conifer needles or Spanish Moss and will usually lay four eggs.
Our final warbler is the Northern Parula, the male of which develops rufous and bluish breast bands in the summer as well as very prominent white eye crescents. I would like to thank Michael McCarthy of the Independent newspaper, whose recent article on these birds (where he bemoans their lack of fame in the animal world) was the inspiration for this attempt to bring these warblers to a wider audience.