Not long ago, I was out on the water when a white blur materialized out of the brilliant blue sky. It was a Cattle Egret that dropped in out of nowhere looking for a little company.
What is it about birds and boats? Cattle Egrets are known to wander. They're a relatively recent arrival from the Old World, after all. Most of the pioneering wave probably made the long trip over on their own, but egrets are no fools. When they see a free ride, they take it.
A ship is a floating island, after all. If you've ever birded a small island or even just an island of good habitat in the middle of inhospitable terrain, you might have seen spooked birds that took off to avoid you, only to realize that there is really is no escape after all. Circling back and staying put is the only option.
A few years ago, George Broussard, Jr. found and photographed a Pied Crow, below, on an oil rig in the Gulf of Mexico. Now, birds have wings and don't read range maps, but I'm sure that even a logically challenged birder would have to admit that there's little chance that this bird took off from sub-Saharan Africa and winged it over to the Gulf of Mexico. If so, I'm not sure why it decided against heading a few more miles onto a continent's worth of land. Maybe it was afraid to cross water?
Crows are funny birds. They live in close contact with humans and are quick to adapt. This bird probably found its way onto a boat that's as big as a small town, and then realized one day that the town was not only moving, it was surrounded on all sides by blue sea. Oops!
Many birds (and other animals) that are common and adaptable and that rely heavily on humans and human-induced changes to the landscape could make the same mistake. House Sparrows, Starlings, House Finches, mockingbirds, and doves are other birds I'd expect as candidates for ocean cruising. Google for similar information and you'll have plenty of good reading on your hands.
Or maybe just hit your favorite waterfront birding location. Gary Broussard came upon this unfamiliar bird in some woods just east of the Sabine River in extreme SWLA back in 2008. It was loud, obnoxious, and attracted to humans, and one look at its feathers was enough to convince anyone that something rougher than the local vegetation had been rubbing against it. The metal surfaces of a ship were mostly likely to blame not only for the frayed feather tips but also the missing chunks along the feather shafts in the tail.
This bird is an Indian House Crow.
Indian as in
from India. This beast is somewhat famous as a ship rider and has apparently gotten footholds in various port cities. It's expected to turn up elsewhere, anywhere, and is considered a potential invasive pest. But who knows? Maybe it doesn't ride ships at all. Maybe it uses its wings and ignores range maps. I say that in sargassum. I mean, sarcasm. Sorry, Skipper.
Birders in Texas are currently having a lively and engaging debate about a recent bird record in their state that might involve a bird that came over on a ship. The record involves a Tropical Mockingbird, a bird from a tropical American species that's normally considered sedentary. Many posters to the Texas list serve have come out in favor of this bird being a genuine wild vagrant. One compared the possibility of the rapid, unprecedented, long-distance, over-water flight of this individual Tropical Mockingbird to the overland range expansion of another mockingbird species, the Northern Mockingbird, which has spread northward as far as Canada at a relatively glacial pace over the past three quarters of a century. Although none of the variables in this analogy actually seem to match, it does offer a jumping off point for debate. Others have countered by noting that analogies generally pit comparable items; as such, looking at other examples of non-migratory birds (Yucatan Vireo for example) that have found their way to Texas from the same basic homeland would make more sense. Whatever the position taken, it's a healthy argument free of even the slightest personal motives whatsoever, the kind of discussion that objective science demands. And it's all made possible by the fact that the bird must somehow have crossed big water, and by the fact that many birders simply can't see any plausible scenario that involves a Tropical Mockingbird that somehow found itself on a ship.
Enter, then, a plausible scenario that involves a Tropical Mockingbird that somehow found itself on a ship and then found itself on the far side of a really big body of water. An interesting account of this mockingbird that almost certainly took a sea cruise across the Atlantic Ocean to Gibraltar can be found at:
http://www.rarebirdspain.net/arbsf067.htm
An interesting aside in the article points out that sedentary species don't fatten up with fuel for long flights in the way that migratory birds do. In other words, sedentary birds generally don't have the flight capacity that migrants do, which might be a key factor in determining how winged visitors arrive here.
However, there's another interesting side note to the discussion about sailing birds that could well be the nut graf here. Note that some Europeans that have weighed in on the Gibraltar bird accept the possibility of ship-assisted travel but favor the possibility of counting the bird as a genuine vagrant, anyway. After all, it seems likely that the bird arranged its own lodging on the ship rather than having been brought on board against its will. I think that's a pretty interesting position. I even considered the same idea when the lust of potentially adding the Indian House Crow to my state list was producing mind-altering listing hormones. I don't know whether I agree with it or not anymore (at my advanced age the levels of listing hormones that affect my personal motives are decreasing rapidly), but in this world of town-sized tankers it might be wise to pay a little practical thought to the particulars of toilers on the sea.
Comments welcome.
