ICTERIDS Icteridae The orioles, blackbirds, cowbirds and allies The Icterids are a large group of strong-billed birds limited in distribution to the New World. They have been called the "New World Blackbirds" or the "Troupials and Allies" or any number of monikers, but it is easiest to think of them "Icterids." The group includes the bright New World orioles, of which the Altamira Oriole (left in a fine shot by Jeri M. Langham) of south Texas and northeastern Mexico is an example. A fair number of orioles are migratory, but this one is not. The group also includes meadowlarks, tropical oropendulas & caçiques, and the highly migratory Bobolink Dolichonyx oryzivorus, along with a wide spectrum of black birds, some of them glossy in plumage; a very common example locally in California is the Brewer's Blackbird (below right). Icterids exhibit a wide variety of lifestyles -- from solitary to densely colonial -- but the longish, slim, and pointed beaks of most rapidly identify them. They are often considered among the most recent of birds, and are sometimes placed at the very end of checklists (eg Sibley & Monroe 1980).



Among complex innovations of this group are nests consisting of delicately-weaved hanging baskets (orioles and some colonial oropendolas & caçiques). In the example to left, a Yellow-rumped Caçique displays its rump feathers at the mouth of its pendent nest in South America, one among a multitude of such nests in a single large isolated tree. While hanging baskets in a colony provides some protection from reptilian predators, and "guards" always posted will drive off some avian predators, some hawks key in to such nests to find themselves "wrapped treats" during the nestling period (anecdotal stories tell of Harpy Eagles doing that).

Many icterids are "black birds" -- the term "Blackbird" is used in a variety of genera -- and some familiar black species are grackles and cowbirds. Parasitic cowbirds will be touched on below, but even the big lumbering grackles are not without interest. Elsewhere on this site is a page delving into variation in Great-tailed Grackle Quiscalus mexicanus, sparked by the recent spread of this species throughout California, including to my home county.

But not all icterids are black. Bright primary colors contrasting with jet black plumage is a common color combination. And this web page serves as a perfect medium to show convergent evolution in two colonial blackbirds, otherwise not closely related and nearly poles apart in distribution: the western North American Yellow-headed Blackbird (left) side-by-side with the southern South American Scarlet-headed Blackbird (right).

The traditional view of cowbirds has been of five species of Molothus (all parasitic) and one huge parasitic cowbird (Giant Cowbird Scaphidura oryzivora). But recent research (Jaramillo & Burke 1999) considers the Bay-winged Cowbird of southern South America (left; taking a bath in a mud puddle) no cowbird at all. Rather, they split another species of Molothrus cowbird to make up the sixth parasitic taxa (indeed, Jaramillo & Burke revised the family upwards to 100+ species).

In North America, the common brood parasite is the Brown-headed Cowbird (fledgling at left being fed by its foster parent, a Dark-eyed Junco, in a Monterey County photo by Brian J. Weed). Brood parasitism is interesting biologically, and has been the subject of several recent scholarly books (Rothstein & Robinson 1998, Ortega 1998). But in California the practice -- combined with major losses in riparian habitat -- has devastated local vireos, flycatchers, and warblers that build open-cup-style nests. A century ago Brown-headed Cowbirds were restricted in California to the Colorado River border with Arizona. But the spread of agriculture in the state opened up habitat and provided food for cowbirds which rapidly spread everywhere (reaching Monterey Co. in the 1920s, the Oregon border by 1960; Laymon 1987). The most susceptible birds declined rapidly, particularly the California races of Willow Flycatcher (Unitt 1987) and Bell's Vireo (Franzreb 1987). Both are severely endangered today. Cowbirds parasitize a wide variety of species; locally, we documented nine hosts during the Monterey Breeding Bird Atlas (Roberson & Tenney 1993) and suspected several more. In a wider view, though, cowbird brood parasitism is fascinating where hosts and parasites have co-evolved in New World tropics.

Finally, I'll note that there are significant identification challenges in the icterids, and particularly migratory species that can spin off vagrants in North America. One set of difficult problems occurs in female orioles; one of my photos was featured as the July 1998 quiz on Joe Morlan's web site (photo and answer now posted there). Another problem group is the North American meadowlarks. There may actually be three species (in which case the Lillian's Meadowlark of the southwest is the easiest to identify), but the problem between traditional Western and Eastern meadowlarks remains nearly intractable. When the yellow throat of Western Meadowlark invades the otherwise whitish malar stripe (as on the larger, left hand bird above), identification is made simpler. But some Westerns (especially in fall) don't show this feature, and then it is hard to find anything that separates a nominate Eastern Meadowlark (above right, top) from a dingy Western (above right, below).

Photos: The male Altamira Oriole Icterus gularis was photographed by Jeri M. Langham in Jan 1980 along the Rio Grande River in Texas. The male Brewer's Blackbird Euphagus cyanocephalus was taking lifting off the grass in Monterey, California, in Apr 1985. The Yellow-rumped Cacique Cacicus cela was displaying at its nest west of Cuiaba, Mato Grosso, Brazil, in Aug 1999. The male Yellow-headed Blackbird Xanthocephalus xanthocephalus was displaying in a colony at Sierra Valley, California, in June 1999, while the male Scarlet-headed Blackbird Amblyramphus holosericeus was doing the same in the Brazilian pantanal in Aug 1999. The two Bay-winged Cowbirds Agelaioides badius were bathing in a mudhole in the Pantanal of Mato Grosso, Brazil, in Aug 1999. The fledgling Brown-headed Cowbird Molothrus ater was being fed by its host, a Dark-eyed Junco Junco hyemalis, at Pt. Lobos, Monterey Co., Calif., in Aug 1989 in a nice photo by Brian J. Weed. As to the Meadowlarks: the first Western Sturnella neglecta was near Ferndale, Humboldt Co., Calif., on 31 Jan 1993; the Eastern S. magna was in Everglades Nat'l Park, Florida, in Jan 1999; and the last Western was at Death Valley Nat'l Park, Calif., on 4 Nov 1979. All photos © D. Roberson except as indicated; photos by Jeri Langham & Brian Weed used by permission; all rights reserved.

Bibliographic note

Family book: Rating HHHH
Jaramillo, Alvaro, and Peter Burke. 1999. New World Blackbirds: The Icterids. Princeton Univ. Press, Princeton, NJ

This is a welcome addition to the bird families of the world literature, authored primarily by Al Jaramillo who is the world's expert on this group. Jaramillo, now a Californian by way of Chile and Canada, has contributed much information already on icterids to birding literature and on the Internet chat lines, so it is nice to see it all brought together in a book. I have not yet studied the book in depth, but my initial impressions are positive. The authors may be a bit of "wild-eyed splitters" from a taxonomic perspective, or, maybe not: although they do add numbers of new species, most of their proposals make sense, as do their generic changes. The Princeton Press books fall just short of the excellent quality of the Oxford series, in my view, both in design and in focus, but this one reaches about as high as this series can get so I give it 4 of 5 possible stars. I was not overwhelmed by the art -- I would like a lot more background, group poses, and behavior -- but the work seems solid and serviceable. The text does summarize biology reasonably well, and it will certainly be referred to when identification problems arise. Many books in "bird families" series are hopeless as references for fine points of identification, and especially when vagrants are involved, but this work seems likely an exception.
Other literature cited:
Franzreb, K. E. 1987. Endangered status and strategies for conservation of the Least Bell's Vireo (Vireo bellii pusillus) in California. W. Birds 18: 43-49.

Laymon, S. A. 1987. Brown-headed Cowbirds in California: historical perspectives and management opportunities in riparian habitats. W. Birds 18: 63-70.

Ortega, C. 1998. Cowbirds and Other Brood Parasites. Univ. of Arizona Press, Tucson.

Roberson, D., and C. Tenney, eds. 1993. Atlas of the Breeding Birds of Monterey County. Monterey Pen. Audubon Soc., Carmel, CA.

Rothstein, S. I., and S. K. Robinson, eds. 1998. Parasitic Birds and Their Hosts: Studies in Coevolution. Oxford Univ. Press, Oxford.

Sibley, C. G., and B. L. Monroe, Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale Univ. Press, New Haven, CT.

Unitt, P. 1987. Empidonax traillii extimus: an endangered subspecies. W. Birds 18: 137-162.




Page created 30 Aug 1999, revised 15 Oct 1999