The solitary sandpiper (Tringa solitaria) is a small shorebird that breeds in North America and migrates long distances to wintering grounds in South America. Solitary sandpipers exhibit interesting behaviors related to breeding, feeding, migration, and defense. Their solitary nature gives them their name, as they are usually found alone rather than in flocks or groups. In this article, we will explore some of the key behaviors and traits of the solitary sandpiper.
General Overview
The solitary sandpiper is a medium-sized sandpiper species, measuring around 8-9 inches in length with a wingspan of about 18 inches. They have brown upperparts, white underparts, and yellow legs. During the breeding season, their plumage has dark streaking on the breast and flanks. They get their common name from their solitary habits, as they are usually seen alone rather than in flocks. However, they may congregate in larger groups during migration.
Solitary sandpipers breed in the boreal forests of Canada and Alaska and winter in South America. They are long distance migrants, making an amazing journey each year between their northern breeding grounds and wintering habitats in South America. The total one-way migration distance can be up to 4,350 miles. They migrate at night and fly at altitudes up to 4,500 feet.
Breeding Behavior
During the breeding season, male solitary sandpipers perform elaborate courtship flights and calls to attract females. Once paired, the female solitary sandpiper lays a clutch of four eggs in a concealed ground nest, usually near water. The nest is a simple scrape in the ground, lined with leaves, grass or moss.
Solitary sandpipers exhibit polyandrous breeding behavior, meaning that one female may mate with multiple males during a single breeding season. The female lays between two and four separate clutches of eggs fertilized by different males. She alone incubates the eggs and cares for the precocial young, who feed themselves as soon as they hatch. The chicks will fledge the nest at around 18-20 days old.
Nesting and Incubation
The female solitary sandpiper creates a shallow nest scrape on the ground near water, usually in a dry location to avoid flooding. Nests are typically lined with grasses, leaves, moss, or other materials. The female will lay 1 clutch per season, containing 3-5 eggs. The eggs are oval shaped with a smooth, glossy surface. Their coloration helps provide camouflage to hide the eggs.
Incubation begins when the last egg is laid and lasts for 18-20 days. The female alone incubates the eggs, while the male plays no parental role. She patiently sits on the nest, rotating the eggs and rearranging the nest lining as needed. If the nest is disturbed, the parent may remove the eggs to a new location by carrying them in her bill one at a time.
Chick Development and Care
Solitary sandpiper chicks are precocial, meaning they are relatively mature and mobile from the moment they hatch. The down-covered chicks leave the nest within a few hours and are able to feed themselves. The female parent will lead them to suitable feeding areas with shallow water and aquatic insects. She shelters and broods them during their early development.
The chicks fledge at around 18-20 days old, when their flight feathers have grown enough for flight. Solitary sandpiper young do not remain with the female for long – usually less than three weeks after hatching. At this point, the female and her brood go their solitary ways in preparation for the fall migration south.
Feeding Behavior
The diet of the solitary sandpiper consists mainly of small invertebrates including insects, crustaceans, mollusks and other aquatic creatures. They forage in a distinctive manner, flashing their wings while wading through shallow water. They move in a start-stop motion, then stop to grab prey from the mud or water surface. This feeding behavior concentrate prey by stirring up the water.
Solitary sandpipers probe into mud and soft soils in search of buried invertebrates. Their bill has sensitive nerve endings to help detect prey under the surface. On land, they may feed on insects disturbed by their movements. They are opportunistic and will eat various flying insects as well.
During migration, solitary sandpipers stopover at wetlands and shorelines to rest and feed. Abundant food sources help them refuel and accumulate fat reserves needed to continue their long distance journey.
Diet Composition
The diet of the solitary sandpiper consists of approximately:
– 70% insects and other arthropods such as beetles, flies, grasshoppers, caterpillars, and insect larvae
– 15% mollusks including snails, slugs, mussels
– 10% crustaceans including amphipods, isopods, shrimp
– 5% other invertebrates including worms, leeches, dragonfly nymphs
They will opportunistically eat other prey like fish eggs and tadpoles. Their ability to capture a variety of small aquatic organisms gives them a diverse nutritional intake.
Foraging Strategies and Techniques
Solitary sandpipers employ several foraging strategies and techniques to catch prey:
– Walk slowly in shallow water flashing wings to stir up and concentrate prey.
– Probe bill into mud or soft soil to catch buried invertebrates.
– Peck at surface and under stones for exposed prey.
– Make short flights from perches to catch disturbed insects.
– Pluck insects from water surface and exposed vegetation.
– Capture flying insects in mid-air.
– Vibrate feet in water to imitate prey and attract small fish.
– Visually search for prey movements in water and vegetation.
Their agile movements and quick reflexes allow them to grab prey in an instant before it disappears back under cover. Solitary sandpipers will forage in all wetland habitats from flooded forests to pond edges.
Migratory Behavior
One of the most fascinating behaviors of the solitary sandpiper is its long distance seasonal migration between North America and South America. They complete this enormous round trip journey every year.
Spring Migration
Each spring, solitary sandpipers leave their wintering grounds in South America and migrate north to their breeding areas in North America. They time their departure to match optimal conditions for nesting and raising young. Males arrive at the breeding grounds first between mid-April to early May to establish territories. Females follow up to several weeks later.
During spring migration, solitary sandpipers stop to rest and feed at wetlands and mudflats to rebuild energy reserves after the long flight. They may congregate in larger groups at choice stopover sites before dispersing to breeding areas.
Fall Migration
In the fall starting in July, adult solitary sandpipers leave the breeding grounds and begin migrating south. They are joined by juveniles a few weeks later after the young have fledged and gained flight strength. Most solitary sandpipers migrate to South America, traveling along coastal routes or overland across the Gulf of Mexico and Caribbean.
They follow chain of wetlands, mudflats, flooded fields and shorelines that provide food resources to fuel the migration. Like spring, they congregate in larger flocks at prime stopover areas. The entire southbound trip takes around two to three months for adults and juveniles.
Navigation and Orientation
Solitary sandpipers employ some remarkable skills to navigate across continents during migration. They are believed to use a combination of the following orientation mechanisms:
– Celestial cues – using the position of the sun and stars
– Geomagnetism – sensing the Earth’s magnetic field
– Landmarks – recognizing sites along migration route
– Circadian rhythms – inner biological clocks
Their ability to orient themselves on migration routes and return to the same breeding and wintering sites each year is an amazing feat of navigation. Ring recovery data show solitary sandpipers exhibit a high fidelity rate to prior breeding and wintering locations.
Behavioral Adaptations
Solitary sandpipers exhibit some key behavioral adaptations that aid their survival in both breeding and nonbreeding habitats:
Cryptic Coloration
Their streaked brown plumage provides excellent camouflage while they nest and feed at the water’s edge. This helps conceal them from potential predators but also hides them from prey as well.
Rapid Escape Flight
When alarmed, solitary sandpipers can burst straight up into fast direct flight to escape threats. This vertical flight maneuver helps them quickly gain altitude and speed away using their pointed wings.
Distraction Displays
To distract predators and intruders away from their nest, solitary sandpipers may perform distraction displays like false broken wing acts. This diverts attention from the actual nest location.
Solitary Territoriality
Their solitary non-flocking behavior during breeding season reduces competition for nesting resources. It also minimizes disturbances to nesting and feeding activities.
Anti-Predator Mobbing
Solitary sandpipers may join together to mob, dive at, or harass potential predators that enter their nesting and foraging areas. This cooperative defense helps deter animals like foxes, raccoons, and birds of prey.
Vocalizations
Solitary sandpipers communicate with a distinct set of vocalizations used in courtship, territorial defense, and alarm situations:
Flight Call
A sharp, whistled “weet” call given by birds in flight, often when migrating at night or changing location.
Courtship Call
A twittering trill used by males when displaying to females in the breeding season. It is given during circular courtship flights.
Alarm Call
A shorter “wee” call or rapid “wee-wee-wee” notes used to signal danger or when mobbing a predator. Companions are alerted to take notice and prepare to escape.
Aggressive Call
A harsh “kweep” given by males to warn territorial intruders and defend nesting areas.
Interaction with Humans
Solitary sandpipers generally avoid human inhabited environments, but may be seen in more rural wetlands, ponds, and flooded fields. They nest in remote boreal forests far from most human activity and have little interaction with people during the breeding season.
During migration they briefly stop at wetlands throughout North and South America. Their shy nature keeps them wary of human observers, maintaining adequate distance. If approached, they readily flush and fly off seeking more secluded areas.
Solitary sandpipers face no major threats from humans and their populations appear stable. As wetland habitats are degraded by pollution, drainage, and development, they may lose some key migratory stopover locations. Maintaining the integrity of wetland ecosystems will benefit solitary sandpipers across their range.
Conclusion
In summary, solitary sandpipers display a variety of fascinating behaviors from their courtship rituals to their marathon migrations between continents. Their solitary breeding habits, cryptic nesting, defensive mobbing, and wetland foraging strategies all contribute to their success as a species. These behaviors and adaptations allow them to thrive across an enormous geographic range. Understanding the behavioral ecology of the solitary sandpiper provides insight into the life history of this widespread yet elusive shorebird. Continued study and observation of their activities will reveal additional details into their remarkable biology and resilience as their habitats change over time.
