A Tale of Two Boobies
A Blue-footed Booby was observed and photographed in Skagit County, Washington, on 6 August 2006 by Ryan Merrill. It was not seen again, notwithstanding a flurry of birder activity searching for it. On 15 August, a booby was found on the I-5 bridge across the Columbia River in Oregon. A passing motorist called it a Bald Eagle. It was picked up and delivered to a local animal hospital, where it was called a Double-crested Cormorant. Finally, it was taken to Portland Audubon’s wildlife rehabilitation center, where it was identified as a Blue-footed Booby. The bird died there after five days, apparently of aspergillosis, and was donated to the Slater Museum (thanks to the Director of Portland Audubon’s Wildlife Care Center, Bob Sallinger). It was picked up by Dennis Paulson and brought to the museum.
Some discussion ensued on the internet trying to determine if the Oregon and Washington birds were one and the same.
The booby at the WIldlife Care Center.
The booby arrives at the museum, a bit bedraggled. We determined that it was an immature from its plumage.
From below, the booby looks even more disheveled, but every attempt was made to turn this ugly duckling into a beautiful swan. It was prepared by Gary Shugart as a specimen, as usual a combination study skin and extended wing. He also saved that part of the skeleton not included in the skin and wing and took a tissue sample to be preserved in an ultracold freezer for future DNA studies. Museums nowadays try to get maximum use of the specimens donated to them.
The booby’s eyes were the cloudy color of the immature, not the pure yellow of the adult.
Boobies, like other members of the order Pelecaniformes, have expansible throat pouches and huge gullets to allow swallowing the rather large fish that make up their diets.
Booby feet are totipalmate, with all the toes included in the very large web. Again, this is a characteristic of the pelecaniform order. Boobies capture fish by diving on them from above, often from high in the air, and they penetrate well below the surface. Then those big feet take over. In adult Blue-footed Boobies, the feet are sky blue (are you surprised?)
A necropsy of such a bird involves making substantial cuts in the skin to expose the abdominal cavity and musculature to look for possible causes of death. The large organ to the right is the stomach, still full of fish from attempts by the Wildlife Care Center to rehabilitate it. The attempts were not successful, but fortunately the center found an appropriate home for the dead bird.
The bird’s immaturity was confirmed by examination of the bursa of Fabricius, an organ at the posterior end of the intestine that serves the immune system in young birds. It decreases in size as a bird matures and is used by ornithologists to determine immaturity in birds that do not change plumage with age.
The booby lies wide open and stuffed with cotton, ready to be sewn up and almost finished. Note the lens cap, a universal scale used by nature photographers, but pay no attention to the feet at the bottom of the photo.
The prepared skin, before being pinned out on a board with the wing closed. The other wing is saved in the extended position. The entire preparation process took about eight hours, including a thorough washing of the skin and removal of some tar or oil from the feathers with turpentine.
How many boobies?
From a comparison with photos of the Skagit County bird, fortunately taken at the time of observation, we have determined conclusively that the Oregon bird was a different bird. How did we do this? Well, it turns out that they weren't even the same species! This is the great value of the donation of a specimen to a museum collection. The Oregon bird is actually a first-year Masked Booby, the first record for the state. Had you already come to that conclusion? If you look back at the photos, you'll see the specimen has much white on the back, a characteristic not shared by Blue-footed Boobies. In particular, the white "collar" behind the neck is diagnostic for immature Masked Boobies, which are otherwise entirely brown above. This bird had already replaced some of the brown feathers on the back with white. It's got a brown neck with a conspicuous white V extending onto the foreneck, characteristic of immature Masked. Probably less than a year old, it would have become entirely white except for its flight feathers and tail, and its bill would have become bright yellow. The very similar Nazca Booby of the Galápagos was considered and rejected because of the white collar, not typical of that species, as well as the much greater distance to its breeding colonies.
Blue-footed Booby from Fernandina, Galápagos (left)
Masked Booby from Dry Tortugas, Florida (right)
Both photos by Dennis Paulson
What are boobies doing in the Pacific Northwest?
We'll never know, of course, how these two boobies reached the Northwest. Boobies are well known to rest on ships on the ocean, and they may travel long distances while doing so. Blue-footed Boobies are resident on the west coast of Mexico, as well as on the Galápagos Islands. Masked Boobies breed on islands off the Mexican west coast, as well as farther west in the Pacific and in the Caribbean. The reason for either of them to visit the Pacific Northwest remains obscure. Large numbers of Brown Pelicans and Heermann’s Gulls move north from Mexico and California each summer to take advantage of the abundant marine resources off the Northwest coast, and perhaps the occasional booby accompanies them. Global warming may make that ever more likely.