581 Shorebirds in the Marine Environment Nils Warnock, Chris Elphick, and Margaret A. Rubega CONTENTS 18.1 Introduction 582 18.2 General Features of Shorebird Biology 582 18.2.1 Foraging 582 18.2.2 Sociality 588 18.2.3 Breeding Systems 588 18.2.4 Nests, Eggs, and Young 588 18.2.5 Survival and Longevity 590 18.3 Shorebirds at the Ocean–Continent Interface 590 18.3.1 Coastal Habitats 590 18.3.1.1 Coastal Wetlands 590 18.3.1.2 Beaches 591 18.3.1.3 Rocky Shores and Coral Reefs 592 18.3.2 Influence of Tides 592 18.3.3 Influence of Oceanography and Climate 593 18.4 Shorebirds on Islands 594 18.4.1 Endemism 594 18.4.2 Visitors 594 18.5 Shorebirds at Sea: Phalaropes 595 18.5.1 Morphological Adaptations of Phalaropes to Life at Sea 595 18.5.2 Pelagic Feeding Biology of Phalaropes 595 18.5.3 Distribution of Phalaropes at Sea 596 18.6 Shorebird Migration across the Marine Environment 596 18.6.1 Common Overwater Migration Routes 597 18.6.1.1 Arctic Ocean 597 18.6.1.2 Pacific Ocean 598 18.6.1.3 Gulf of Mexico and the Caribbean Sea 599 18.6.1.4 Atlantic Ocean 599 18.6.1.5 Indian Ocean 599 18.6.2 Behavior While Migrating 600 18.6.2.1 Orientation and Timing 600 18.6.2.2 Flock Size, Flight Speed, and Altitude 600 18.7 Conservation of Marine Shorebirds 601 18.7.1 Problems at the Ocean–Continent Interface 601 18.7.1.1 Commercial Harvesting of Shorebird Prey 602 18.7.1.2 Hunting 602 18.7.1.3 Pollution 602 18.7.1.4 Coastal Development 604 18 © 2002 by CRC Press LLC 582 Biology of Marine Birds 18.7.2 Problems at Sea: Phalaropes 604 18.7.3 Influence of Climate Change and Sea-Level Rise 605 18.7.4 Future Shorebird Protection in Marine Environments 605 Acknowledgments 606 Literature Cited 606 18.1 INTRODUCTION The purpose of this chapter is to review the ecology of shorebirds in the context of their relationship to the marine environment. The shorebirds are a group of families usually placed in the order Charadriiformes along with gulls, skuas, terns, skimmers, and auks (e.g., del Hoyo et al. 1996, American Ornithologists’ Union 1998). An alternative view, based on studies of DNA-DNA hybrid- ization, is to treat this entire group as a suborder within the order Ciconiiformes (Sibley and Monroe 1990). The shorebirds are traditionally thought of as a monophyletic group, although this may not be the case and the relationships among the families within the order remain uncertain (American Ornithologists’ Union 1998). Depending on taxonomic source, shorebirds are variously divided into about a dozen families. Three of these are of particular significance to this discussion: the Scolopacidae (sandpipers, snipes, and phalaropes) and Charadriidae (plovers) which include 71% of all shorebird species, and the Haematopodidae (oystercatchers), with 11 species found largely in marine environments (Table 18.1). Even though their name conveys an affinity to water, shore- birds are not traditionally considered marine birds (Burger 1984a). However, the taxonomic, ecological, and behavioral characteristics of the two groups indicate much in common, and shore- birds (especially the phalaropes) have many traits that suit them for a life on or near salt water. Overall, 58% of shorebird species are known to use marine habitats regularly, either during breeding or nonbreeding seasons (Table 18.1). Thirty-nine percent of breeding shorebirds sometimes or always nest along the coast, while 66% of nonbreeding shorebirds use the coast for stopovers or nonbreeding grounds (Burger 1984a). The majority of shorebirds migrate (62%, Table 18.1), and most of these birds cross marine bodies. Two shorebird species, the Red-necked Phalarope (Phalaropus lobatus) and the Red Phalarope (P. fulicaria), spend up to 75% of their time directly on the open ocean, more than many species traditionally referred to as seabirds. 18.2 GENERAL FEATURES OF SHOREBIRD BIOLOGY 18.2.1 F ORAGING On land and at sea, shorebirds tend to be omnivorous, although invertebrates are their dominant prey. In a survey of shorebird diets in the Western Hemisphere, the most common taxonomic classes of invertebrate prey eaten were the Insecta, Malacostraca, Gastropoda, Polychaeta, and Bivalvia (Skagen and Oman 1996), but other important prey for shorebirds include small amphibians, fishes, seeds, and fruit. The four species of seedsnipes apparently only eat plant matter (Fjeldså 1996), while at the other extreme sheathbills often eat carrion and small penguin chicks (Burger 1996). Shorebirds typically obtain their prey by locating it visually and plucking it from the water column, ground, or other surfaces, or by probing in mud. There is considerable interspecific and occasional intraspecific variability in bill morphology (Burton 1974, Sutherland et al. 1996, Rubega 1997) that results in a wide variety of feeding habits. Many species have straight bills for making rapid thrusts through soft substrates or firm soils or for picking prey off the water’s surface (see also Pelagic Feeding Biology of Phalaropes). The curved bills of species like the Long-billed Curlew (Numenius americanus) and the Whimbrel (N. phaeopus) are similar in shape to the burrows of invertebrates such as ghost shrimps (Callianassa californiensis) and probably facilitate capture of these prey species. Many scolopacids have bills with tactile and chemosensitive receptors at their © 2002 by CRC Press LLC Shorebirds in the Marine Environment 583 TABLE 18.1 Shorebird Families of the World, Whether They Migrate, and Their Use of Marine Habitat Common Name Migratory Marine Thinocoridae Rufous-bellied Seedsnipe Attagis gayi No No White-bellied Seedsnipe A. malouinus No No Grey-breasted Seedsnipe Thinocorus orbignyianus Unknown No Least Seedsnipe T. rumicivorus Yes No Pedionomidae Plains-wanderer Pedionomus torquatus No No Scolopacidae Eurasian Woodcock Scolopax rusticola Yes No Amami Woodcock S. mira No No Rufous Woodcock S. saturata No No Sulawesi Woodcock S. celebensis No No Moluccan Woodcock S. rochussenii No No American Woodcock S. minor Yes No Solitary Snipe Gallinago solitaria Yes Unknown Latham's Snipe G. hardwickii Yes Unknown Wood Snipe G. nemoricola Yes No Pintail Snipe G. stenura Yes Unknown Swinhoe's Snipe G. megala Yes No Great Snipe G. media Yes Unknown Common Snipe G. gallinago Yes Yes African Snipe G. nigripennis No Unknown Madagascar Snipe G. macrodactyla No Unknown South American Snipe G. paraguaiae Yes No Noble Snipe G. nobilis No No Giant Snipe G. undulata Unknown No Andean Snipe G. jamesoni No No Fuegian Snipe G. stricklandii Unknown Unknown Imperial Snipe G. imperialis No No Jack Snipe Lymnocryptes minimus Yes No Chatham Snipe Coenocorypha pusilla No No Subantarctic Snipe C. aucklandica No Unknown Black-tailed Godwit Limosa limosa Yes Yes Hudsonian Godwit L. haemastica Yes Yes Bar-tailed Godwit L. lapponica Yes Yes Marbled Godwit L. fedoa Yes Yes Little Curlew Numenius minutus Yes Yes Eskimo Curlew N. borealis Yes Ye s Whimbrel N. phaeopus Yes Yes Bristle-thighed Curlew N. tahitiensis Yes Yes Slender-billed Curlew N. tenuirostris Yes Yes Eurasian Curlew N. arquata Yes Yes Long-billed Curlew N. americanus Yes Yes Far Eastern Curlew N. madagascariensis Yes Yes Upland Sandpiper Bartramia longicauda Yes No Spotted Redshank Tringa erythropus Yes Yes Common Redshank T. totanus Yes Yes Marsh Sandpiper T. stagnatilis Yes Ye s Common Greenshank T. nebularia Yes Yes © 2002 by CRC Press LLC 584 Biology of Marine Birds Nordmann's Greenshank T. guttifer Yes Yes Greater Yellowlegs T. melanoleuca Yes Yes Lesser Yellowlegs T. flavipes Yes Ye s Solitary Sandpiper T. solitaria Yes No Green Sandpiper T. ochropus Yes N o Wood Sandpiper T. glareola Yes No Terek Sandpiper Xenus cinereus Yes Yes Common Sandpiper Actitis hypoleucos Yes Yes Spotted Sandpiper A. macularia Yes Yes Grey-tailed Tattler Heteroscelus brevipes Yes Yes Wandering Tattler H. incanus Ye s Yes Willet Catoptrophorus semipalmatus Yes Yes Tuamotu Sandpiper Prosobonia cancellata No Yes Ruddy Turnstone Arenaria interpres Yes Yes Black Turnstone A. melanocephala Yes Yes Short-billed Dowitcher Limnodromus griseus Yes Yes Long-billed Dowitcher L. scolopaceus Yes Ye s Asian Dowitcher L. semipalmatus Yes Yes Surfbird Aphriza virgata Yes Yes Great Knot Calidris tenuirostris Yes Yes Red Knot C. canutus Yes Yes Sanderling C. alba Yes Yes Semipalmated Sandpiper C. pusilla Yes Yes Western Sandpiper C. mauri Yes Yes Little Stint C. minuta Yes Yes Red-necked Stint C. ruficollis Ye s Yes Temminck's Stint C. temminckii Yes Yes Long-toed Stint C. subminuta Yes Yes Least Sandpiper C. minutilla Ye s Yes White-rumped Sandpiper C. fuscicollis Yes Yes Baird's Sandpiper C. bairdii Yes Yes Pectoral Sandpiper C. melanotos Yes Yes Sharp-tailed Sandpiper C. acuminata Yes Yes Purple Sandpiper C. maritima Yes Yes Rock Sandpiper C. ptilocnemis Yes Yes Dunlin C. alpina Yes Yes Curlew Sandpiper C. ferruginea Yes Yes Stilt Sandpiper Micropalama himantopus Yes No Buff-breasted Sandpiper Tryngites subruficollis Yes No Spoon-billed Sandpiper Eurynorhynchus pygmeus Yes Yes Broad-billed Sandpiper Limicola falcinellus Ye s Yes Ruff Philomachus pugnax Ye s Yes Wilson's Phalarope Phalaropus tricolor Yes No Red-necked Phalarope P. lobatus Yes Yes Red Phalarope P. fulicaria Yes Yes Rostratulidae Greater Painted-snipe Rostratula benghalensis Yes Unknown South American Painted-snipe Nycticryphes semicollaris Unknown No Jacanidae African Jacana Actophilornis africanus No No TABLE 18.1 (Continued) Shorebird Families of the World, Whether They Migrate, and Their Use of Marine Habitat Common Name Migratory Marine © 2002 by CRC Press LLC Shorebirds in the Marine Environment 585 Madagascar Jacana A. albinucha No No Lesser Jacana Microparra capensis No No Comb-crested Jacana Irediparra gallinacea Unknown No Pheasant-tailed Jacana Hydrophasianus chirurgus Yes No Bronze-winged Jacana Metopidius indicus No No Northern Jacana Jacana spinosa No No Wattled Jacana J. jacana No No Chionidae Pale-faced Sheathbill Chionis alba Ye s Yes Black-faced Sheathbill C. minor No Yes Burhinidae Stone Curlew Burhinus oedicnemus Yes No Senegal Thick-knee B. senegalensis No No Water Dikkop B. vermiculatus No Yes Spotted Dikkop B. capensis No No Double-striped Thick-knee B. bistriatus No No Peruvian Thick-knee B. superciliaris No No Bush Thick-knee B. grallarius No Yes Great Thick-knee Esacus recurvirostris No Yes Beach Thick-knee E. giganteus No Yes Haematopodidae Eurasian Oystercatcher Haematopus ostralegus Yes Yes Canarian Black Oystercatcher H. meadewaldoi Unknown Yes African Black Oystercatcher H. moquini No Yes American Black Oystercatcher H. bachmani Ye s Yes American Oystercatcher H. palliatus Yes Yes Australian Pied Oystercatcher H. longirostris No Yes Variable Oystercatcher H. unicolor No Yes Sooty Oystercatcher H. fuliginosus No Yes Blackish Oystercatcher H. ater No Yes Magellanic Oystercatcher H. leucopodus Unknown Yes Chatham Oystercatcher H. chathamensis No Yes Ibidorhynchidae Ibisbill Ibidorhyncha struthersii No No Recurvirostridae Black-winged Stilt Himantopus himantopus Yes Yes Black Stilt H. novaezelandiae No Unknown Banded Stilt Cladorhynchus leucocephalus Yes Ye s Pied Avocet Recurvirostra avosetta Yes Yes American Avocet R. americana Yes Ye s Red-necked Avocet R. novaehollandiae No Yes Andean Avocet R. andina Unknown Yes Charadriidae Eurasian Golden Plover Pluvialis apricaria Yes Yes Pacific Golden Plover P. fulva Yes Yes American Golden Plover P. dominica Ye s Yes Grey (Black-bellied) Plover P. squatarola Ye s Yes TABLE 18.1 (Continued) Shorebird Families of the World, Whether They Migrate, and Their Use of Marine Habitat Common Name Migratory Marine © 2002 by CRC Press LLC 586 Biology of Marine Birds Red-breasted Plover Charadrius obscurus Yes Yes Common Ringed Plover C. hiaticula Yes Yes Semipalmated Plover C. semipalmatus Yes Yes Long-billed Plover C. placidus Yes Yes Little Ringed Plover C. dubius Yes Yes Wilson's Plover C. wilsonia Yes Yes Killdeer C. vociferus Yes Yes Black-banded Plover C. thoracicus No Yes St Helena Plover C. sanctaehelenae No No Kittlitz's Plover C. pecuarius Unknown Yes Three-banded Plover C. tricollaris Unknown Yes Forbes's Plover C. forbesi Ye s No Piping Plover C. melodus Yes Yes Chestnut-banded Plover C. pallidus Yes Yes Kentish (Snowy) Plover C. alexandrinus Yes Ye s White-fronted Plover C. marginatus Ye s Yes Red-capped Plover C. ruficapillus Unknown Yes Malaysian Plover C. peronii No Yes Javan Plover C. javanicus No Unknown Collared Plover C. collaris No Yes Double-banded Plover C. bicinctus Yes Yes Puna Plover C. alticola Unknown Yes Two-banded Plover C. falklandicus Yes Yes Lesser Sandplover C. mongolus Ye s Yes Greater Sandplover C. leschenaultii Yes Yes Caspian Plover C. asiaticus Ye s No Oriental Plover C. veredus Yes Yes Eurasian Dotterel C. morinellus Ye s No Mountain Plover C. montanus Ye s No Rufous-chested Plover C. modestus Yes Yes Hooded Plover C. rubricollis No Yes Shore Plover C. novaeseelandiae No Yes Red-kneed Dotterel Erythrogonys cinctus Unknown No Tawny-throated Dotterel Oreopholus ruficollis Yes Unknown Wrybill Anarhynchus frontalis Yes Yes Diademed Plover Phegornis mitchellii Unknown No Inland Dotterel Peltohyas australis Unknown Unknown Black-fronted Dotterel Elseyornis melanops Unknown No Magellanic Plover Pluvianellus socialis Yes Yes Northern Lapwing Vanellus vanellus Yes Yes Long-toed Lapwing V. crassirostris No No Yellow-wattled Lapwing V. malarbaricus No No Javanese Wattled Lapwing V. macropterus Unknown No Banded Lapwing V. tricolor Unknown No Masked Lapwing V. miles Yes Yes Blacksmith Lapwing V. armatus No Yes Spur-winged Lapwing V. spinosus Yes Yes River Lapwing V. duvaucelii No No Black-headed Lapwing V. tectus No No Spot-breasted Lapwing V. melanocephalus No No TABLE 18.1 (Continued) Shorebird Families of the World, Whether They Migrate, and Their Use of Marine Habitat Common Name Migratory Marine © 2002 by CRC Press LLC Shorebirds in the Marine Environment 587 Grey-headed Lapwing V. cinereus Yes No Red-wattled Lapwing V. indicus Yes No White-headed Lapwing V. albiceps Yes Unknown African Wattled Lapwing V. senegallus Unknown No Lesser Black-winged Lapwing V. lugubris Yes No Greater Black-winged Lapwing V. melanopterus Yes Yes Crowned Lapwing V. coronatus No No Brown-chested Lapwing V. superciliosus Yes No Sociable Lapwing V. gregarius Yes Unknown White-tailed Lapwing V. leucurus Yes Unknown Pied Lapwing V. cayanus No Yes Southern Lapwing V. chilensis Unknown Unknown Andean Lapwing V. resplendens No No Dromadidae Crab Plover Dromas ardeola Yes Yes Glareolidae Egyptian Plover Pluvianus aegyptius Ye s Yes Double-banded Courser Smutsornis africanus No No Bronze-winged Courser Rhinoptilus chalcopterus Ye s No Three-banded Courser R. cinctus No No Jerdon's Courser R. bitorquatus No No Cream-colored Courser Cursorius cursor Yes No Burchell's Courser C. rufus No No Temminck's Courser C. temminckii Ye s No Indian Courser C. coromandelicus No No Collared Pratincole Glareola pratincola Yes Yes Oriental Pratincole G. maldivarum Yes Yes Black-winged Pratincole G. nordmanni Yes Unknown Madagascar Pratincole G. ocularis Yes Yes Rock Pratincole G. nuchalis Unknown Yes Grey Pratincole G. cinerea No Yes Small Pratincole G. lactea Yes Yes Australian Pratincole Stiltia isabella Yes Yes Note: Under Migrate, Yes = species known to migrate regularly (note that if part of a species migrates and part does not, the species would be listed under Yes), No = species known not to migrate, and Unknown = species for which it is unclear if the species is migratory. Under Marine, Yes = species known to use marine habitat regularly (marine habitat defined as beginning with coastal estuaries, mudflats, and other types of marine shoreline extending into the pelagic zone), No = species not known to use marine habitat regularly, and Unknown = species for which it is unclear if the species regularly uses marine habitat. Information summarized from del Hoyo et al. (1996) including accounts by Baker-Gabb (1996), Burger (1996), Fjeldså (1996), Hockey (1996), Hume (1996), Jenni (1996), Kirwan (1996), Knystautas (1996), Maclean (1996), Pierce (1996), Rands (1996), van Gils and Wiersma (1996), and Wiersma (1996). TABLE 18.1 (Continued) Shorebird Families of the World, Whether They Migrate, and Their Use of Marine Habitat Common Name Migratory Marine © 2002 by CRC Press LLC 588 Biology of Marine Birds tips — thus prey can be found by touch and smell (von Bolze 1968, Heezik et al. 1983), and even pressure gradients (Piersma et al. 1998). Species with these adaptations tend to feed both during the day and at night (Warnock and Gill 1996, van Gils and Piersma 1999). 18.2.2 SOCIALITY Generally, shorebirds are gregarious when not breeding and territorial during the breeding season. However, gregarious nonbreeding shorebirds will often vigorously defend small feeding territories, abandoning them to rejoin flocks when tides cover feeding areas or predators appear (Myers et al. 1979). Some species are colonial breeders, especially members of the Recurvirostridae (avocets and stilts), Dromadidae (crab-plovers), Chionidae (sheathbills), and Glareolidae (coursers and pratincoles) families (Burger 1996, Maclean 1996, Pierce 1996, Rands 1996). In an extreme example, perhaps the entire population of Banded Stilts (Cladorhynchus leucocephalus) in eastern Australia, up to 100,000 birds, will attempt to breed at one inland lake (Alcorn and Alcorn 2000). This event happens when the normally dry interior alkali lakes of the region receive rain, creating breeding habitat and stimulating blooms of invertebrates. 18.2.3 BREEDING SYSTEMS Breeding systems vary considerably among shorebird species. Most shorebirds are monogamous, with individuals forming a pair bond with just one individual each breeding season and both parents caring for the young (Emlen and Oring 1977, Oring and Lank 1984). In many monogamous species, pair bonds are strong and often persist from year to year (e.g., Eurasian Oystercatchers Haematopus ostralegus, Ens et al. 1996; Semipalmated Sandpipers Calidris pusilla, Sandercock 1997). Polygyny, in which some males mate with more than one female within a single breeding season, is found in at least 25 species, most of which are sandpipers, snipes, and woodcocks (Emlen and Oring 1977, Oring and Lank 1984). In a few of these species, birds gather at leks, where males display to females from small, vigorously defended territories (Hoglünd and Alatalo 1995). Cop- ulation does not involve pair-bonding and males play no role in parental care. Of shorebirds with lek behavior, the best known are the Buff-breasted Sandpiper (Tryngites subruficollis, Lanctot and Laredo 1994), the Great Snipe (Gallinago media, Hoglünd and Alatalo 1995), and the Ruff (Philo- machus pugnax, Van Rhijn 1991), all northern latitude breeders. Polyandry, in which a female mates with multiple males (Emlen and Oring 1977), occurs in the phalaropes, all jacanas except for the Lesser Jacana (Microparra capensis), and in some plovers, painted-snipes, and sandpipers (Baker-Gabb 1996, Jenni 1996, van Gils and Wiersma 1996, Wiersma 1996). The males of these species generally incubate the eggs and raise the young. A few species practice rapid multiple clutch polygamy in which males and females have access to multiple mates within a season, and each may simultaneously incubate separate clutches. Perhaps the best- documented case of this occurs with the Temminck’s Stint (Calidris temminckii), where both males and females exhibit multiclutch behavior with multiple mates within the breeding season (Hildén 1975, Breiehagen 1989). Often the breeding system varies among individuals within a species. For example, many individuals of nominally “polygamous” species may mate monogamously, and polygamy may occur in some species that are generally monogamous. Males and females of the monogamous Eurasian Oystercatcher often engage in extra-pair copulations, although DNA fin- gerprinting has shown that few chicks (1 of 65 chicks) are not actually fathered by the dominant male partner (Heg et al. 1993, in Ens et al. 1996). 18.2.4 NESTS, EGGS, AND YOUNG The typical shorebird nest is a bowl-like scrape in the ground (often near water) that is lined with pebbles, shells, grasses, or leaves. A few species, such as the Solitary Sandpiper (Tringa solitaria) in North America and the Wood Sandpiper (T. glareola) in Eurasia, are tree-nesters. These birds © 2002 by CRC Press LLC Shorebirds in the Marine Environment 589 do not build nests, but instead use abandoned nests of passerines. Some species of plovers that breed in hot environments such as Africa’s White-fronted Plover (Charadrius marginatus) and Australia’s Inland Dotterel (Peltohyas australis) cover their nests with sand, probably to regulate temperatures and hide them from predators (Wiersma 1996). Sheathbills also often lay nests in caves, crevices, and petrel burrows to avoid having their nests depredated by skuas or trampled by penguins (Burger 1996). Shorebirds lay one to four pyriform eggs (most lay four-egg clutches) that are extremely well camouflaged in shades of off-white, buff, and olive, marked with black or brown splotches (Harrison 1978, Cramp and Simmons 1983). Incubation periods of nesting shorebirds last 15 to 40 days depending on the species and location. Hatching usually takes 12 to 48 h from hole-pipping to actual hatch, with all chicks leaving their eggs within 24 h of each other. Most shorebird chicks are precocial (sheathbills hatch asynchronously and are semiprecocial; Burger 1996) and covered with down at hatching. Generally, they leave the nest within a day or two (sometimes hours) of hatching to forage with at least one parent (often the male), and are brooded by the parents for at least the first few days after hatching. Most shorebird chicks feed on their own after hatching, but there are exceptions. Oystercatcher and sheathbill chicks rely on their parents for food until they fledge (Burger 1996, Hockey 1996, Safriel et al. 1996; Figure 18.1). The Magellanic Plover (Pluvianellus socialis) is unique among shorebirds in that parents apparently regurgitate food from their crop to chicks until after the chicks fledge (Jehl 1975). The Burhinidae (thick-knees, Hume 1996), Glareolidae (coursers and pratincoles, MacLean 1996), Dromadidae (crab plovers, Rands 1996), and some species — snipes and woodcocks — of Scolopacidae (sandpipers, snipes, and phalaropes, Piersma 1996b) provide food for their young for about the first week of life. As with incubation, the timing of fledging varies among shorebird species. Smaller sandpipers and plovers fledge at 14 to 26 days; larger sandpipers and plovers fledge at 28 to 45 days, while some jacanas, oystercatchers, thick-knees, and stilts may take 50 days or more (del Hoyo et al. 1996). Many species breed in their first spring (at approximately 1 year of age); some (especially larger species) do not mature sexually until 2 to 5 years of age. In species where nesting habitat is limited, individuals may have to wait several years before acquiring high-quality breeding sites. In some Eurasian Oystercatchers, it may take up to 10 years before a bird is able to successfully get a mate and a breeding territory (Ens et al. 1996). FIGURE 18.1 An adult American Oystercatcher pries a limpet off a rock while its chick waits to be fed. Note, the oystercatcher has broken a piece off the limpet shell to insert the blade-like, laterally flattened bill tip. (Drawing by J. Zickefoose.) © 2002 by CRC Press LLC 590 Biology of Marine Birds 18.2.5 SURVIVAL AND LONGEVITY Annual adult survival rates of shorebirds typically range from 60 to 70% in small species and 85 to 95% in larger species; survivorship of shorebirds in their first year is often less than 50% (Evans and Pienkowski 1984, Evans 1991, Jackson 1994, Sandercock and Gratto-Trevor 1997, Warnock et al. 1997, Reed et al. 1998). Shorebirds are relatively long lived at 4 to 10 years, with some individuals surviving for 20 years or more. In one amazing example, a Eurasian Oystercatcher that was banded as a nestling in 1949 was killed by a Eurasian Sparrowhawk (Accipiter nisus) in 1992 at the age of 43 years and 6 months (Exo 1993). Even small sandpipers can be long lived as evidenced by a female Least Sandpiper (Calidris minutilla, the world’s smallest shorebird with a mass of 19 to 25 g) that was observed breeding at a minimum age of 16 years (Miller and McNeil 1988, Cooper 1994). 18.3 SHOREBIRDS AT THE OCEAN–CONTINENT INTERFACE The lives of many shorebird species are intimately connected to the ocean, especially at the boundary between land and sea. Shorebirds use a wide variety of coastal habitats, ranging from rocky surf-battered shorelines, to mangrove swamps and sheltered coastal bays. Some species breed in coastal areas, but the majority use these habitats primarily during the nonbreeding season. Because of the relatively low freezing point of salt water, littoral environments often provide accessible food despite cold weather. Also, ambient temperatures in coastal areas frequently are warmer than sites farther inland. Consequently, coastal wetlands and the ocean shore continue to be desirable wintering grounds long after interior wetlands at similar latitudes have become unsuitable for foraging shorebirds. 18.3.1 COASTAL HABITATS 18.3.1.1 Coastal Wetlands Coastal wetlands include some of the most productive habitats in the world, and shorebirds are found in virtually every kind of coastal wetland. The nontidal portions of saltmarshes and coastal lagoons provide breeding and foraging habitat for many species. Tidal mudflats are home to foraging flocks, which can number into the hundreds of thousands of birds. Tidal marsh breeders include a few species of oystercatchers and some tringine sandpipers, such as Common Redshank (Tringa totanus) and Willet (Catoptrophorus semipalmatus). Coastal lagoons support a wider variety of breeding species, including avocets, stilts, phalaropes, and plovers. Shorebirds commonly interact with the marine environment on estuarine mudflats, where vast numbers gather during migration and winter in some parts of the world. For example, 3 to 4 million Western Sandpipers (Calidris mauri) may stop at the Copper River Delta in Alaska during a 4-week period in early spring (Bishop et al. 2000). These birds are en route to their tundra nesting grounds and join millions of other shorebirds also stopping at the delta (Isleib 1979). During the winter, over 2 million shorebirds use the vast tidal flats of the Banc d’Arguin in Mauritania, western Africa (Wolff and Smit 1990). In Asia, West Africa, Central and South America, and other tropical areas, mangroves and their associated mudflats are important habitats for shorebirds (Hepburn 1987, Parish et al. 1987, Morrison et al. 1998). Estuaries are highly productive and shorebirds take advantage of the abundance of soft sediment invertebrate prey that they can find by probing in the mud. Different shorebird species can be found in subtly different parts of marshes. Larger species, such as curlews and godwits, with their long legs and bills, are capable of feeding in deeper water than small sandpipers and plovers. Some species tend to feed in small flocks at the edge of a marsh where they can pick at the base of small clumps of vegetation, whereas others are found in larger © 2002 by CRC Press LLC [...]... aspects of shorebirds is their biology during passage over large bodies of water With the exception of phalaropes, shorebirds rarely touch the water during migration Well over half of all shorebird species are migratory (Table 18. 1), and many © 2002 by CRC Press LLC Shorebirds in the Marine Environment 597 FIGURE 18. 3 Major marine migration routes of shorebirds and known wintering areas of Red-necked... shorebirds These effects include increased urbanization spurred by human population growth and the introduction of mammalian predators As this happens these sites become much less suitable for birds that have adapted to a predator- and human-free environment (see Conservation of Marine Shorebirds, below; J C Coulson, Chapter 4, this volume) 18. 5 SHOREBIRDS AT SEA: PHALAROPES While the majority of shorebirds... in The Birds of North America (A Poole and F Gill, Eds.) Academy of Natural Sciences, Philadelphia; American Ornithologists’ Union, Washington, D.C © 2002 by CRC Press LLC 608 Biology of Marine Birds COOKE, R G., AND M BUSH 1989 Out -of- season Red–necked Phalaropes in central Panama Journal of Field Ornithology 60: 39–42 COOPER, J M 1994 Least Sandpiper (Calidris minutilla) No 115 in The Birds of North... declines in numbers of phalaropes off the coast of the northwestern United States (Wahl and Tweit 2000) raises the specter of a more widespread problem The disappearance of millions of birds suggests that they are as vulnerable as any marine seabird to anthropogenic alterations of marine environments 18. 7.3 INFLUENCE OF CLIMATE CHANGE AND SEA-LEVEL RISE One of the biggest unknowns in modern conservation... 2002 by CRC Press LLC 594 Biology of Marine Birds El Niño and the Western Pacific Oscillation (Mlodinow et al 1999) To what degree these climatic events also result in significant mortality of shorebird populations is unknown 18. 4 SHOREBIRDS ON ISLANDS 18. 4.1 ENDEMISM Biologists often think of islands as important sites for evolutionary differentiation of terrestrial species Seabirds as a group do not... 19: 2 MLODINOW, S G., S FELDSTEIN, AND B TWEIT 1999 The Bristle-thighed Curlew landfall of 1998: climatic factors and notes on identification Western Birds 30: 133–155 © 2002 by CRC Press LLC 612 Biology of Marine Birds MORRISON, R I G 1984 Migrations systems of some New World shorebirds Pp 125–202 in Behavior of Marine Animals Vol 6 Shorebirds: Migration and Foraging Behavior (J Burger and B L Olla,... Atlas of Nearctic Shorebirds and Other Waterbirds on the Coast of Panama Special Publication, Canadian Wildlife Service, Ottawa MOSS, S 1998 Predictions of the effects of global climate change on Britain’s birds British Birds 91: 307–325 MURPHY, R C 1936 Oceanic Birds of South America, Vol II American Museum of Natural History, New York MYERS, J P 1985 Sanderlings do not drive across the Gulf of Mexico... distribution and abundance of the marine prey of shorebirds, it is probable that these periodic events have profound impacts on shorebird populations Briggs et al (1987) noted that in the fall of 1982, phalarope densities off the coast of California were almost a quarter of their normal level, and attributed this decline to the ENSO event of 1982–1983 During this same ENSO event, Red-necked Phalaropes were... 347 in The Birds of North America (A Poole and F Gill, Eds.) Academy of Natural Sciences, Philadelphia; American Ornithologists’ Union, Washington, D.C GOSS-CUSTARD, J D 1977 The ecology of the Wash III Density related behaviour and the possible effects of a loss of feeding grounds on wading birds (Charadrii) Journal of Applied Ecology 14: 721–739 GOSS-CUSTARD, J D., AND M E MOSER 1988 Rates of change... Conservation of Marine Birds of the North Pacific (K Vermeer, K T Briggs, K H Morgan, and D Siegal-Causey, Eds.) Canadian Wildlife Service Special Publication, Ottawa UNDERHILL, L G., A J TREE, H D OSCHADLEUS, AND V PARKER 1999 Review of Ring Recoveries of Waterbirds in Southern Africa Avian Demography Unit, University of Cape Town, Cape Town, South Africa VAN GILS, J., AND T PIERSMA 1999 Day- and night-time . 602 18. 7.1.4 Coastal Development 604 18 © 2002 by CRC Press LLC 582 Biology of Marine Birds 18. 7.2 Problems at Sea: Phalaropes 604 18. 7.3 Influence of Climate Change and Sea-Level Rise 605 18. 7.4. suitable for birds that have adapted to a predator- and human-free environment (see Conservation of Marine Shore- birds, below; J. C. Coulson, Chapter 4, this volume). 18. 5 SHOREBIRDS AT SEA:. Altitude 600 18. 7 Conservation of Marine Shorebirds 601 18. 7.1 Problems at the Ocean–Continent Interface 601 18. 7.1.1 Commercial Harvesting of Shorebird Prey 602 18. 7.1.2 Hunting 602 18. 7.1.3 Pollution