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UPCOMING OPPORTUNITY:
Join us for another
Winter Hummingbird Expedition to Costa Rica
in November/December 2005 or February 2006

HUMMINGBIRD MORNINGS
On the weekend of 5-7 August 2005
we'll be at Woodlands Nature Station at
Land Between the Lakes, KY/TN
(Click on the logo at left for details, additonal 2005 presentations, and info
about booking "Hummingbird Mornings for your own facility in 2006.)

APPRECIATING BLUE GROSBEAKS

People often ask us about our "favorite" bird, assuming we will answer Ruby-throated Hummingbird because of our long-term banding study and involvement with Operation RubyThroat: The Hummingbird Project. We like hummers--a lot!--but they're probably not our favorite.

We also have a soft spot for Blue Jays (below left), a bird species the typical backyard birder dislikes because they are aggressive, boisterous, and eat tons of bird seed. Having studied jays for four long, cold winters in Minnesota, we have a favorable opinion about this bright-colored corvid, and it bothers us that many apparently are succumbing to West Nile Virus. We're likewise fond of all those colorful spring parulids--especially Canada Warblers--that migrate over Hilton Pond on their way to northern breeding grounds, but we're ever on the lookout for Great-crested Flycatchers because that species is first one wife Susan Hilton ever identified on her own. With regard to vocalizations, we contend there is no finer song in nature than the flute-like melody of the Wood Thrush, and we are enchanted by the antics of Brown-headed Nuthatches (right). Obviously we would be hard-pressed to choose our "favorite" from all these birds just mentioned, especially when we throw in the Blue Grosbeak. Now THERE'S a bird we truly appreciate--for lots of reasons--not the least of which is that we caught two this week in our nets at Hilton Pond Center.

All text & photos © Hilton Pond Center

If you further ask most folks about their favorite "blue-hued" bird, they likely toss out the garrulous Blue Jay and then give Eastern Bluebird the edge over Indigo Bunting or Black-throated Blue Warbler. A few veteran birders might vote for Belted Kingfisher or the increasingly elusive Cerulean Warbler, but we doubt many would tap the Blue Grosbeak as their favorite. Too bad, because we've long appreciated this interesting species and wish more people would sign up for our Blue Grosbeak Fan Club.

Like other birds with similar names, the Blue Grosbeak has a massive bill, olive green in juveniles (top photo); in adults it is two-toned (various photos below), the upper mandible black and the bottom one an indescribable gray. (Note also the young bird's soft-looking, light-colored "gape"--the fleshy area at the corner of the mouth.) First-year birds of both sexes are uniformly brown all over (above) and resemble the female--except she has prominent rusty wing bars; juveniles an females are among the most nondescript of all North American songbirds.

During their first winter, young males acquire varying amounts of blue feathers (above and below). When they return to Hilton Pond Center after overwintering in the Neotropics, they have a blue-and-brown calico appearance.

By their third year, male Blue Grosbeaks acquire their full adult plumage (two photos below), which includes a heavy black mask, well-developed chestnut wing bars (two per wing), and body feathers that are essentially all blue--although third-year birds may retain a slight tinge of brown here and there. Regardless of age, males in particular often raise their crown feathers slightly when stimulated, giving the appearance of a small crest.

We've often joked that Blue Grosbeaks look like Indigo Buntings on steroids, but that's not really the case. Adult buntings lack the brown wing bars that appear in grosbeaks, and the plumage of a male bunting (below left) bears several almost metallic shades of blue while that of the grosbeak is flatter and more uniform. Both species have a prominent two-tone bill in the adult and both have nested at Hilton Pond Center. Their overall breeding ranges are quite different, however, with the Blue Grosbeak nesting across the entire southern two-thirds of the U.S. and into Mexico, and the Indigo Bunting breeding from Canada to Texas and northern Florida--but only east of the Rocky Mountains. These two species also occupy similar winter ranges that include Mexico and all of Central America, with grosbeaks also wandering to Cuba and buntings to the West Indies.

We usually know when Blue Grosbeaks have arrived at Hilton Pond when we hear their distinctive, sharp chink. On a few occasions, we've even heard the male sing his warbling courtship song, which sounds a little like that of a House Finch. Back when we had power lines running across the property, we often saw Blue Grosbeaks AND Indigo Buntings perched on wires in close proximity to each other, singing to prospective mates that were listening in shrubby areas below. Since then we've had the power lines removed and the brushy habitat has been replaced by a young woodland, so grosbeaks and buntings are two more bird species that are less common locally--thanks to vegetative succession.

We use the old weed-eater to maintain a few open areas on the 11 acres that make up Hilton Pond Center, cutting during every third year just to vary the habitat and encourage plant and animal diversity. Last summer--in one of those false meadows--we found a Blue Grosbeak nest two feet off the ground in a fast-growing Sweetgum sapling (below). Actually, we spotted the nest in November--well after its occupants were long gone to the tropics--and mostly because a nest-adorning white paper bag became apparent when autumn leaves fell. Grosbeaks typically place a piece of white matter in their woven grass nests--a behavior they share with Blue Jays--but for grosbeaks this ornamentation more often consists of a snakeskin or two.

If you like nature, you may taken interest in all this info about Blue Grosbeaks--scientific name Guiraca caerulea--but we still haven't gotten to why we happen to like them so much. For one thing, we rarely band them, having caught only 60 in the past 24 years at Hilton Pond Center, so it's a rare treat to have one in-hand. For another, we like their feistiness; they almost always try to nip our knuckles when we photograph them and we gotta admire a bird with that much pluck. But our main interest in this species goes back almost 30 years to 1 June 1978 when we discovered a Blue Grosbeak nest near an old farm pond a few miles east of York. At that time, we were just getting into birding and were excited to find an active nest of this relatively uncommon species. Our real thrill, however, was that along with four pale blue eggs of the grosbeak the nest held a spotted one laid by a Brown-headed Cowbird. Even though grosbeaks apparently are frequent hosts to socially parasitic cowbirds, what was most interesting about this nest was it was the first known record of cowbird parasitization within in York County SC. We managed to get an account of our finding published in a bird journal. Needless to say, this pleased us greatly and encouraged us to continue our new infatuation with studying birds--and now you know the reason we really do appreciate these big-billed Blue Grosbeaks.

All text & photos © Hilton Pond Center