The buff-breasted sandpiper is a medium-sized shorebird that breeds in the Arctic tundra and migrates long distances to wintering grounds in South America. Despite their extensive migrations and interesting behaviors, buff-breasted sandpipers remain mysterious in many ways. Here are some fascinating facts about these birds:
Migration
– Buff-breasted sandpipers undertake an extraordinary migration each year, traveling up to 12,500 miles roundtrip between their Arctic breeding grounds and South American wintering areas. Their migrations are among the longest of any shorebird species.
– They migrate in flocks, sometimes numbering in the hundreds of birds. These flocks represent a significant portion of the global population, which is estimated at around 15,000 birds.
– Most buff-breasted sandpipers winter in the grasslands of southeastern South America, especially in Argentina, Uruguay, and southern Brazil. A smaller number spend the winter in areas like Bolivia, Paraguay, and Peru.
– During migration they stopover at key wetland sites to rest and feed. Important stopover sites include areas of the Great Plains in central North America.
Breeding
– Buff-breasted sandpipers breed in the dry tundra habitats of North America’s Arctic regions, including Alaska and Canada. They are found nearer to the coast than many other shorebirds.
– Males perform dramatic aerial displays during the breeding season to attract females. These displays involve flying high in the sky and then plunging down in zig-zags, while making whining sounds.
– Nests consist of small depressions in the ground, lined with vegetation and leaves. Males construct several nests for the female to choose from.
– Females lay a clutch of 4 eggs, which are incubated by both parents for around 22 days. The precocial young leave the nest soon after hatching.
Diet
– On their Arctic breeding grounds, buff-breasted sandpipers mainly eat insects like beetles, flies, grasshoppers, and larva. They also consume leaves, seeds, and berries.
– While migrating, they feed on insects, marine invertebrates like brine shrimp, and seeds. They use their distinctive short bills to probe into mud to find food.
– On their wintering grounds in South America, their diet shifts to consist mostly of grass seeds and shoots. They also forage on grasslands and agricultural fields.
Conservation Status
– Buff-breasted sandpipers have an extremely limited breeding distribution—their global population occupies a breeding range smaller than the state of Kansas. This makes them vulnerable to any negative impacts on their Arctic habitat.
– Probably less than 4,000 birds use the main U.S. stopover region in the spring, underscoring the importance of protecting key migration habitats.
– The combination of their small population size and restricted range has led the buff-breasted sandpiper to be classified as Near Threatened on the IUCN Red List. Ongoing population monitoring is needed.
– Potential threats on their migration and wintering grounds include habitat loss to agriculture, pesticides, pollution, and hunting pressure.
Species Characteristics
– As their name suggests, buff-breasted sandpipers have pale, buff-colored underparts that contrast with their dark upperparts. Their black legs further add to their distinctive look among shorebirds.
– During the breeding season, the chestnut neck and underparts become even richer in color, while white spots develop on the back. Their bills also take on a bright yellow-orange hue.
– Juveniles have a more muted, gray-brown appearance than adults. First-year birds gain some adult plumage after their first migration south.
– They are a tactile species and preen each other extensively. Large “sunning” flocks can be seen resting on the ground and preening communally.
– Their calls include a “wit-wit” alarm call and various soft whistles. On the breeding grounds, males perform flight displays accompanied by high-pitched whines.
Discovery and Naming
– The buff-breasted sandpiper was first scientifically described in 1817 by Louis Jean Pierre Vieillot, based on a specimen from Paraguay. However, Native Americans were already quite familiar with the species before its formal discovery.
– Its genus name Tryngites comes from the Greek word tryngites meaning “living in solitude,” referring to the bird’s habit of breeding in solitary pairs, away from other shorebirds.
– The common name refers to the buff coloration on the bird’s underparts, while “sandpiper” denotes this as a typical member of that shorebird group.
Physical Description
The buff-breasted sandpiper is distinctive in appearance compared to other shorebirds:
Size
– Length: 7.5-9 inches
– Wingspan: 17-20 inches
– Weight: 1.5-3.6 ounces
Medium-sized by shorebird standards. Similar in size to a sanderling but with a heavier, fuller body shape.
Plumage
– Breeding plumage: Underparts are buff-colored with neat black spotting. Back is mottled black and brown with white spotting. Face, throat, and neck are rich chestnut. Yellow-orange bill.
– Non-breeding plumage: Paler overall, with buff underparts fading to white on the belly. Less distinctive patterning on the back. Dull gray legs and feet.
– Juvenile plumage is brownish-gray above with pale underparts. First-year birds gain some adult-like patterning through successive molts.
Bill
Short, straight dark bill used for probing in mud or turf. Bill becomes bright yellow-orange during breeding season.
Legs and feet
Black legs and feet. No hind toe as in other sandpipers. Toes are webbed for surface swimming.
| Size | 7.5-9 inches long | 17-20 inch wingspan | 1.5-3.6 ounces weight |
|---|---|---|---|
| Plumage | Buff underparts | Spotted/mottled back | Orange bill in breeding season |
| Legs and feet | Black legs/feet | No hind toe | Webbed front toes |
Behavior and Habits
The behaviors and habits of buff-breasted sandpipers include:
Social Behavior
– Highly social species, especially seen in large flocks during migration. These flocks may contain hundreds of birds.
– Communal roosting and preening in “sunning” flocks are common. Birds stand close together and preen each other extensively.
– Latitude for individual distance varies seasonally. Tightest groups form during premigratory staging.
Locomotion
– Fast, erratic flight style with rapid wingbeats interspersed with gliding. Different from the steady flight of many sandpipers.
– When feeding, they walk steadily and purposefully. Feed with head lowered peering down to spot prey.
– Swim buoyantly but infrequently, mainly near nesting sites. Use feet simultaneously in “paddle” motion when swimming.
Migration Behavior
– Perform incredibly long migrations in large flocks between Arctic breeding and South American wintering grounds.
– Make relatively few stops during fall migration, but have many long stopovers during northbound spring migration.
– Use certain key wetland habitats as migratory staging areas to rest and feed.
Vocalizations
– Give a piercing “wit-wit” call when alarmed.
– Various soft whistles used, as well as grunting sounds.
– Males have a distinctive high-pitched whine used during aerial breeding displays.
Foraging and Diet
– Use short bills to probe into turf or mud to find food just under the surface. Also pick insects off vegetation.
– Prey includes beetles, flies, grasshoppers, larva, shrimp, seeds, leaves, and berries.
– Diet varies seasonally based on habitat. More insects in summer, more plant food in winter.
| Social Behavior | Highly communal species | Roosts and preens in large groups | |
|---|---|---|---|
| Locomotion | Fast, erratic flight | Steady walking gait while feeding | Swims infrequently |
| Migration | Travels incredibly long distances | Few stops in fall, more in spring | Uses key wetland staging habitats |
| Vocalizations | “Wit-wit” alarm call | Whistles and grunts | Whining aerial display calls |
| Foraging | Probes mud/turf for invertebrates | Picks insects from vegetation | Seasonally varied diet |
Breeding and Reproduction
The breeding ecology and reproduction of buff-breasted sandpipers include:
Breeding Season
– Nest during the short Arctic summer, from around late May through July.
– Birds arrive on breeding grounds already paired up from spring migration.
– Earlier nesting than many shorebirds to fit brood-rearing into short Arctic summer.
Courtship and Mating
– Males perform dramatic aerial displays, diving and zig-zagging from great heights with whining vocalizations. This excites females on the ground.
– Monogamous pairs form, with females inciting multiple males into aerial displays before choosing a mate.
– Pairs reunite on breeding grounds in successive years and may mate for life if both survive.
Nest Sites
– Nests are small depressions on the ground lined with leaves, lichens, and grasses. Built by male but chosen by female.
– Usually placed on relatively barren, elevated tundra mounds with good visibility. Near water but avoid marshy areas.
Clutch Size and Incubation
– Single clutch of about 4 eggs per season. Eggs are buff-colored with brown spotting.
– Both sexes incubate eggs for 21-23 days until hatching. Males incubate at night, females during the day.
– Precocial young leave nest within 2 days to feed themselves. Parents continue caring for them.
| Breeding Season | Late May through July | Earlier than many shorebirds | |
|---|---|---|---|
| Courtship | Male aerial displays | Monogamous pair bonds | Females incite multiple suitors |
| Nest Sites | Small ground depressions | Lined with vegetation | On elevated tundra mounds |
| Clutch and Incubation | 4 eggs per clutch | Both sexes incubate for 21-23 days | Precocial downy chicks |
Population Status and Conservation
Some key facts about the population status and conservation needs of buff-breasted sandpipers:
Population Size and Trends
– Global population estimated at 15,000 individuals.
– North American Breeding Bird Survey shows 1.7% annual decline 1966-2015.
– However, survey results may undersample this species’ remote tundra habitat.
Population Threats
– Small population size and limited breeding distribution increase vulnerability.
– Habitat loss on migration and wintering grounds due to agriculture and development.
– Disturbance and hunting pressure on South American grasslands.
– Pollution and changing climate affecting Arctic nesting grounds.
Protected Legal Status
– Classified as Near Threatened on IUCN Red List.
– Protected under Migratory Bird Treaty Act in U.S. and Canada.
– Considered a Species of Special Concern in many U.S. states.
Conservation Actions Needed
– Protection of key migratory stopover habitats in the Great Plains.
– Monitoring and management of wintering grounds in South America.
– Stewardship of breeding grounds as Arctic oil and gas exploration expands.
– Continued population surveys and banding studies to track trends.
| Population Status | Estimated global population of 15,000 | Showing slight declines in surveys | |
|---|---|---|---|
| Threats | Small population size | Habitat loss in migration and winter areas | Disturbance and hunting pressure |
| Conservation Status | Near Threatened on IUCN Red List | Protected under migration treaties | Species of Special Concern in U.S. states |
| Conservation Needs | Protection of key migratory habitats | Monitoring of wintering grounds | Stewardship of Arctic breeding areas |
Research Priorities and Knowledge Gaps
Despite being relatively well-studied, some important gaps remain in scientific knowledge of buff-breasted sandpipers:
Migration and Geography
– Precise migration routes and timing need better documentation. More tracking studies of individual birds can help fill gaps.
– Locations of key stopover sites are not fully known. Need to identify networks of important wetlands used during migration.
– Wintering grounds have not been extensively surveyed. Remote grasslands of central South America are little studied.
Population Status
– Global population estimates are quite uncertain due to remoteness of breeding areas.
– Better monitoring protocols for Arctic breeding grounds need to be developed to detect population trends.
– Banding studies to estimate survival rates and study longevity have been limited so far.
Behavior and Ecology
– Molecular genetic research on their mating system and pair bonding dynamics is still needed.
– More study of wintering ecology and diet on South American grasslands is required.
– Effects of disturbance like aircraft overflights near breeding areas should be investigated.
| Migration | Precise migration routes and timing | Locations of key stopover wetlands | Surveys of remote wintering areas |
|---|---|---|---|
| Population Status | Improved global population estimates | Better monitoring in the Arctic | Increased banding and survival studies |
| Behavior and Ecology | Genetic mating system analysis | Wintering ecology research | Studies of disturbance impacts |
Conclusion
In summary, the buff-breasted sandpiper is a fascinating Arctic visitor prized by birders for its unique appearance and extraordinary migrations. However, it faces conservation challenges due to its limited population size and habitat threats along its migration route. Addressing key gaps in scientific knowledge can help support effective management efforts for this rare shorebird species into the future. Increased research and monitoring of buff-breasted sandpiper populations is needed to ensure the species persists and retains its amazing marathon migrations across continents. This high-flying tundra traveler serves as an inspiring example of the miracles of bird migration.
