Phalaropes of San Francisco

Autumn 2005 Volume 25, Number 3 Phalaropes of San Francisco Bay By Hilary Papendick And Sarah Warnock slender necks, small heads, dark, needle-sharp Think of a shorebird, and what comes to bills, and lobed toes that are similar to grebes mind? A long-legged sandpiper, probing the and coots. Due to the rather unorthodox mating soft substrate of a protected lagoon, or perhaps strategy of phalaropes, females in breeding plum- a snowy plover hunkered down in a dune? age are more brightly colored than males. Less commonly thought of as a shorebird is a tight little ship of a bird, bobbing in open seas, leagues from the nearest shore... Phalaropes, the only free-swimming shorebird, are one of the oddest - and fascinating - members of the diverse shorebird order Charadriformes, a group that also includes oystercatchers, stilts and avocets, sandpipers and plovers. Often considered their own family, the three species of phalaropes are tucked taxo- nomically in at the end of the shorebird section of field guides. Red phalaropes, plump little tomato-colored birds with white cheeks and yellow bills, are the most pelagic (ocean-going) of the three, and the rarest in San Francisco Bay. Their visits are accidental, and often tied to storm events. In the case of red phalaropes, Phalaropes are only territorial during Red-necked phalarope the Don Edwards San Francisco Bay National breeding season, and females will fight fero- Photo USFWS Wildlife Refuge means exactly that - a refuge ciously for males during courtship. The femalesʼ from tempestuous seas. brighter colors are as much for attracting males More common in the San Francisco Bay as for intimidating other females. are Wilsonʼs phalaropes and the more abundant As a group, shorebirds exhibit almost red-necked phalaropes, which appear regularly every mating strategy known to ornithologist each spring and fall as they make their way - including monogamy, in which both male and across hemispheres between breeding and female share responsibilities of caring for young, wintering areas. Their natural migration stopover and polygamy, in which one male will mate with sites, - hyper-saline lakes and ponds packed with several females and has no hand in rearing the brine shrimp and brine flies - have been dwin- young. Phalaropes are one of the few bird species dling over the past century. Food resources and that exhibit polyandry - an unusual strategy for calm waters in San Francisco Bayʼs salt ponds birds since it involves the laying of more than have become an important alternative. one clutch by a female within a short time span, each with a different male. Because each clutch Identification and Breeding can weigh nearly as much as the female, this is Both red-necked and Wilsonʼs phalaropes no mean feat. The females then leave incubation are small (7.5” - 9.5”), triangular birds with and chick-rearing to the males. Continued page 2 1 Phalaropes of San Francisco Bay continued Feeding Behaviors reach a few weeks of age and can fend for Each shorebird group forages for in- themselves, they leave the breeding grounds. vertebrates in its own characteristic manner. Females depart before the males. The juveniles Sandpiper bills are equipped with chemosensory undergo their first migration on instinct alone. nerves at the tip to help them locate invertebrates Alaskan red-necked phalaropes migrate along hidden in the mud. The large eye of plovers helps the west coast of the U.S. and Canada. Millions them to spot fast-moving prey which they pluck have been recorded in the Prince William Sound neatly from the surface of mud or sand. area in spring on their way to their northern breeding grounds. Most Alaskan red-necked Phalaropes, on the other hand, call for phalaropes spend the winter in the Pacific waters take-out. By spinning like a top on the surface of South America.. Less ocean-oriented than the of water, their food is delivered directly to them. red-necked, Wilsonʼs phalaropes migrate through As phalaropes spin, the water directly underneath the Great Basin to the highland plains of Bolivia is displaced to the outside, and replaced by and Argentina. A phalaropeʼs one-way migration deeper waters. Along with the deeper waters may cover a distance of as much as 8000 miles. come invertebrates from lower down in the water Considering they may live as long as 15 years, a column. phalarope could log a quarter of a million migra- Now within reach of the phalaropeʼs tory miles, or the Considering they needle-sharp bills distance between and quick reflexes, Earth and the may live as long the invertebrates moon. Pretty good are captured and for a bird that as 15 years, a swallowed using a weighs only a few newly discovered ounces! The east- feeding mecha- ern range of the phalarope could nism that was red-neckedʼs fall first described in migration route log a quarter of a phalaropes. Called overlaps with the surface tension western range of million migratory transport, this the Wilsonʼs in behavior occurs San Francisco miles, or the so quickly it was Bay. Phalaropes of only discovered both species begin through the use of to arrive in early distance between Photo Eric Taylor, USFWS high-speed video. Red phalarope July, and numbers After plucking the peak in late July Earth and the invertebrate from the water, phalarope bills do and August. By the end of October, almost all not clamp down, and there is no conveyer belt to phalaropes will have departed for the wintering moon. carry the prey item to the throat. So, how does grounds. the prey get up the 1 1/2” bill? Video stills show the prey is captured Threats to phalarope populations along with a drop of water. The water molecules Trends in phalarope populations are dif- on the surface of the drop adhere to the lower ficult to determine but are likely declining, as are and upper mandibles of the birdʼs bill. Instead of most shorebird species, due to habitat loss and closing the bill phalaropes actually open it wider, degradation throughout their breeding, migration increasing surface area of the drop. As the bill and wintering areas. The propensity of shore- widens, the base of the bill becomes narrower birds such as the phalaropes to gather in huge and the water molecules, seeking a surface to concentrations in a single migration area like cling to, are drawn up the mandible. The inver- Prince William Sound leaves them especially tebrate, still packaged inside the droplet, goes vulnerable to human-caused disasters, such as oil along for the ride. Total elapsed time: 2/100th of spills. For many years, up to 20,000 red-necked a second. phalaropes also stopped to feed and rest in the western Bay of Fundy in New Brunswick. In the Range and Migration mid-1980s, bird numbers decreased, and by the The red-necked phalarope nests through- 1990s, not a single phalarope appeared at the out Alaska and Canadaʼs northern territories. site. The disappearance of a group of phalaropes Wilsonʼs phalaropes breed in the in the western is alarming. More information is needed to interior of the U.S. and Canada, from north- determine whether the phalaropes simply shifted east California to the Dakotas to northern to a new feeding site or whether a catastrophe Saskatchewan. Both species construct grass-lined has occurred to the population. nests, nestled among low vegetation near the In California, the loss of Owenʼs Lake, the edge of small ponds or lakes. Once the chicks near-loss of Mono Lake, and the possible loss of 2 3 Phalaropes of San Francisco Bay continued the Salton Sea due to water diversions means a ing active commercial salt production. Because Hilary Papendick has a B.A. potentially huge loss of the phalaropesʼ favored salinity levels determine which invertebrates and from Scripps College and migration stopover areas. These invertebrate- fish can survive, and pond depth determines the attended the School for Inter- packed hyper-saline lakes play a crucial role in availability of the prey to different bird predators, national Training in Ecuador, the migration of grebes and other shorebirds. a diversity of ponds leads to a diversity of birds. and the University of Otago Political and scientific collaborations are Low salinity ponds support a variety of in New Zealand. She has underway to preserve enough of these unusual invertebrates as well as fish, which in turn sup- taught environmental educa- yet critical habitats for both the birds and for the port sandpipers, terns, pelicans, and waterfowl. health of local human populations. At higher salinities, fish and most invertebrates tion in Alaska, Montana, and People are mobilizing to reduce another can no longer survive, but brine shrimp, brine fly Ecuador, where she received threat to millions of night-migrating birds, and water boatmen populations explode. These a grant to improve education including phalaropes. Fatally attracted to tall, large invertebrate blooms are visible even from programs in a small coastal brightly-lit buildings, especially in wet weather, the air. Taking advantage of the feast are the town. Hilary was recently an phalaropes are in danger of collision with win- phalaropes, black-necked stilts, eared grebes by education intern at PRBO dows that reflect the night sky, and of becoming the hundreds of thousands, and flocks of delicate and is now working at the confused by the lights of buildings. Unable to Bonaparte gulls. Montana Outdoor Science escape the brightness, they grow exhausted and The recent acquisition of more than 15,000 School in Bozeman. fall to the ground, prey for urban scavengers. acres of South Bay salt ponds provides an Birders and building managers in large cities unprecedented opportunity to restore marshlands Sarah Warnock, Director of across the nation are working together to reduce and improve the Bay ecosystem.

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