Sanderling Vs Dunlin: Key Differences Explained
Sanderlings and Dunlins are both small shorebirds often seen along coastlines which can make identification difficult especially from a distance. However, there are enough differences between these two bird species to make it fairly easy to distinguish between the two.
By patiently observing these two birds and taking note of their differences which include differences in size, behaviour, habitat and plumage you will be able to tell these two fascinating bird species apart.
Keep reading to find out more.
Table of Contents
Key Takeaways
- Sanderlings are slightly larger than Dunlins
- Dunlins have downward curving black bills
- Sanderlings have shorter, thicker straight bills
- Sanderlings can often be seen running along the tideline in search of food
- There are distinct differences in their colourations with Sanderlings having paler backs and heads than Dunlins
What Is The Difference Between A Sanderling And A Dunlin?
There are a number of differences in these two bird species which can make identifying one species from another quite a simple task. What makes it easier is that these shoreline birds are often spotted side by side.
This makes it easy to see their differences. The differences between the Sanderling and the Dunlin include;
Visual Differences
Dunlins are smaller and more compact in size with a shorter, thicker straight bill. They have relatively long wings which adds to their more agile appearance.
Sanderlings are slightly larger, have black legs, pale grey backs (brown in summer) and white underbellies with a black mark on their shoulder which lines up with their folded wing.
Dunlins have a slightly downward curving black bill, a streaked grey-brown head and back (brighter in summer), a streaked underbelly (black in summer) and dark legs.
During the breeding season Dunlins have a distinctive black belly patch, a reddish-brown back and crown.
Sanderlings are likely to be seen running along the tideline very fast.
Differences In Habitat
Sanderlings are mainly found on sandy beaches, along coastlines or on inland bodies of water during migration. They are typically seen running backwards and forwards with the waves on sandy beaches picking at the surface in search of food.
Sanderlings are often spotted in large flocks along the shoreline.
Dunlins are more versatile in their habitat and are found on mudflats, estuaries, tundra and marshland during the breeding season and migrationary period. They are also often spotted along the shore, but their preferred habitat is mudflats, tidal marshes and estuaries.
They will typically be probing in the mud or sand with their long bill searching for food.
Both of these species of birds have long migratory patterns and are only summer visitors to the UK. Sanderlings have one of the longest migrations of any shorebirds and travel from the Arctic tundra to beaches in South America and Africa.
Dunlins also migrate long distances but have a more varied range. They breed in Arctic and Subarctic regions and migrate to coastal areas across Europe, Asia and North America.
Nests & Eggs
Female Sanderlings select a suitable nesting site close to shores of freshwater lakes or ponds. She makes a shallow scrape nest in an exposed location on stony ground which is cup shaped.
The nest is lined with leaves, moss, lichen and dry twigs as well as pebbles. She will lay a clutch of around 3 to 4 dull green or olive-brown or greenish-blue eggs that are streaked with black or brown spots. The eggs are incubated for around 23 to 27 days.
Male Dunlins typically select the nesting site which is usually in vegetation of tundra regions often near clumps of grass. He will then construct a simple scrape nest which is lined with leaves, sedges and grasses.
The female will then select the best nest and then lay a clutch of around 3 to 4 olive, brown, blue-green or buff eggs that are covered in light brown or orange-brown spots. The eggs are incubated for around 20 to 22 days.
The chicks of both species are precocial which means they hatch with their eyes open and covered in downy feathers.
Bird Calls
The call of the Sanderling is a quiet, soft, high-pitched “peep” sound which can sound quite melodious and is mainly heard during the breeding season.
Dunlins have a wider range of calls including trills and more melodious soft “peep” sounds which are also mainly heard during the breeding season.
Size & Weight
Sanderlings are slightly larger than Dunlins with an average length of around 20 to 21 cm and a wingspan of around 36 to 39 cm. They weigh anywhere between 50 to 60 grams.
Dunlins are around 16 to 20 cm in length with an average wingspan of between 35 to 40 cm. They weigh around 40 to 50 grams.
However, the size and weight of these two birds are not a reliable way to distinguish between the two. Visual cues are a better indicator than size.
SEE ALSO: Wheatear Life Cycle: Nest Building To Fledging (and everything in between)
Frequently Asked Questions
The Sanderling is similar to the Dunlin. They are both shoreline birds and can both be seen along the shore searching for food. However, Sanderlings have short, straight black bills whereas Dunlins have longer, thinner, slightly curved black bills.
Sanderlings do fly in compact flocks in order to protect themselves from predatory attacks from Peregrine Falcons. The flock will manoeuvre erratically to evade the predators.
Dunlin do fly in flocks during their migratory flights with other small wading birds.
