Avian Ocean Hitch-Hikers

Reprinted from The Condor
Volume 38, January 1936

Jack von Bloeker, while at Berkeley submitted a scientific essay to Joseph Grinnell, editor of the Condor. It is incredible that this article is published in a scientific journal because it helps to explain why the Song Sparrow nests on other Channel Islands, but not on Catalina Island. Both von Bloeker and Grinnell were absolutely incredible vertebrate zoologists. My research has shown that Jack von Bloeker and Joseph Grinnell spent a considerable time at sea. They did zoological studies at Catalina Island and they spent considerable time on boats that sailed to the California coastal islands in search of birds, reptiles, amphibians, mammals, and beetles. They both explored many Channel Islands. Jack von Bloeker was even a student at Berkeley under Joseph Grinnell. Here is a quote about the ocean by Grinnell that could also have been said by von Bloeker: "Those of us who have undertaken voyages across the ocean will readily recall the almost constant presence of goonies, or albatrosses, which fly along in the wake of the boat closely scrutinizing the sea surface for any sort of refuse that may serve them as food." That quote came from a Grinnell article entitled: Goonies of the Desert.

Avian Ocean Hitch-hikers. -- On May 25, 1935, the Iota Kappa Nu Society of the Los Angeles Junior College chartered a small boat for an excursion to Catalina Island to observe birds. En route to the island and about one-half miles from San Pedro, we observed a San Diego Song Sparrow (Melospiza melodia cooperi) flying westward about twenty-five yards from the starboard side of the boat. We watched it for some time and noted that it gradually approached the boat and finally perched half-way up on the rope ladder leading to the top of the mast. It was content to ride for the major part of the trip, alternating its perch at intervals between the top of the mast and the rope ladder. When we were within half a mile of Avalon, it left the boat and continued its flight toward the island.

During the rest of the day we observed several Song Sparrows in and about the shrubbery at the Catalina Aviary and other points near Avalon. In the evening, about 6 p.m., upon returning to the Hotel Saint Catherine float where our boat was waiting, one lone Song Sparrow (race?) was observed hopping about near the end of the pier. Perhaps it was our "hitch-hiker." Who knows? Song Sparrows have been recorded as probably migrants from the mainland to Catalina previously, by Meadows (Condor, 36, 1934, p.40). A twenty-two mile flight over water by a bird of such localized habits as a Song Sparrow, it seems to me, is unusually long, it may be that small boats travelling to Catalina Island play a large part in aiding these birds in their offshore pioneering, as recorded here.

The "hitch-hiker" recorded above recalls a similar incident to my mind, in which a California Yellow Warbler (Dendroica aestiva brewsteri) figured. It was on May 30, 1927, on the annual excursion of the San Diego Society of Natural History to Los Coronados Islands, off Lower California. Shortly after leaving San Diego Harbor, several members of the party observed a Yellow Warbler flying a short distance from the boat. The bird was seen at intervals for some time, maintaining approximately the same speed as our launch, about eight knots per hour. After we were nearly five miles offshore, the warbler approached the boat and finally perched on the roof of the pilot's cabin. There it rested for half an hour or so and then took to flight again. Three times it rested on the boat during the trip. The last time it flew off, about two miles from Corpus Christi (North Coronado Island), it increased its speed of flight and soon was lost to sight beyond the bow of the boat toward the island.
-- Jack C. von Bloeker. Museum of Vertebrate Zoology, University of California, October 16, 1935.