Why do some black birds have white bellies? 10 Beautiful Examples!
Perhaps you have spotted a black bird with a white underbelly on your garden fence, in a tree at the park, or flying out over the ocean? Black and white birds are common, but black birds with white underbellies are part of a more exclusive club.
Black and White Coloration in Animals
Although we tend to focus on animals with bright coloration or striking patterns such as flamingos or peacocks, there are a vast number of animals with a simple black and white palette. There can be many interesting, evolutionary reasons behind this high contrast trend including:
- A warning to predators to keep away
- A way of repelling insects
- A camouflage technique
- A way to make an animal look more fearsome by enhancing certain features
Dark coloration in animals is due to pigments in the skin called melanin. This pigment helps protect animals from potentially harmful UV light from the Sun, warm up more quickly in colder areas, and allows some species to blend into their naturally dark surroundings, for example lava plains. From a human perspective, we can think of this as wearing dark-coloured formal clothing to blend into the hustle and bustle of business-dense city centres!
On the other hand, light coloration is the exact opposite – it is caused by a lack of pigmentation in an animal’s skin. This is a common characteristic in animals living in environments with little or no light, such as cave-dwelling animals. Genetic mutations cause the skin to lack pigment. This lack of pigmentation can be advantageous in environments where white coloration allows animals to blend in, consequently becoming prevalent in a population through the process of natural selection.
Black and White Coloration in Birds
Birds with black and white coloration have evolved these palettes and patterns for the same kinds of reasons stated above – predator avoidance, camouflage etc. However, there could be a few advantages to possessing black and white tones which are specific to birds:
- Black feathers help birds to warm up more quickly when they bask in the Sun, helping them to fly more efficiently.
- As well as causing dark coloration, melanin can strengthen feathers when it binds to a protein called keratin – the material a feather is made from. This combination of melanin and keratin make a feather more resistant to wear and tear.
- The keratin that feathers are made from is naturally colourless, making feathers without pigmentation appear white. This can be a big advantage to waterbirds which are at risk from predation from below – the white makes them harder to discern against the light-coloured sky above.
You may notice that the majority of the birds on our list today are waterbirds. This is no coincidence! Possessing a white belly is a great advantage for birds which swim or sit on the surface of lakes or seas. This is a characteristic of many seabirds such as Puffins and Razorbills. Underwater predators including some species of shark frequently prey on seabirds but can have problems discerning them against the sky. Imagine swimming underwater and looking up towards the sky. It will appear very pale and therefore a white-bellied bird floating on the surface of the water would be quite difficult to see!
Diving birds like Little Auks hunt for fish below the water’s surface – a pale belly can also camouflage birds against the sky, making it harder for potential prey to see them coming. Similarly, shorebirds who stand and wait for prey to swim by may benefit from the natural camouflage white bellies give them.
10 Black Birds with White Bellies
What these birds lack in terms of bright colours, they make up for in fascinating lifestyles, exotic locations, and intriguing characteristics. Let’s have a look at 10 amazing examples…
1. Common Magpie
The Common or Eurasian Magpie is an incredibly common species. It is likely that people who live almost anywhere throughout the north of the Eurasian continent will be familiar with this bird. Perhaps its survival success and vast range are due to it being one of the most intelligent species with a brain-to-body mass ratio which matches great apes and aquatic mammals! Among their impressive range of talents is their ability to use tools, recognise themselves in mirrors, organise themselves into groups as an anti-predator strategy, and store food away for later use.
Some group names for magpies include:
Next time you see a gulp of magpies, be sure to look out for their white underbellies and listen to their striking range of noisy “chac-chac” calls.
For more information please see: https://animalia.bio/eurasian-magpie
2. Black Phoebe
The Black Phoebe is a small and inconspicuous bird, with a range from southern North America through areas of northern South America. Its colouring is mostly black-brown with a white underbelly that looks as if it has been dipped in snow or white paint.
This species is a type of flycatcher but is also known to catch small fish. It frequents watercourses including streams, lakes and estuaries. Black Phoebes practice tail pumping – a characteristic technique which is used in this species as a signal to potential predators. The bobbing up and down of the tail tells a predator that the Black Phoebe is aware of its presence, and indicates that the individual is in good health and hence will be hard to catch. This clever tactic is obviously working – the Black Phoebe population is growing and spreading north!
Find out more here: https://www.allaboutbirds.org/guide/Black_Phoebe/overview
3. Tree Swallow
When the light reflects of this beautiful species’ plumage, its black back will shine iridescent blue! The sleek and shiny tree swallow is resident during breeding season throughout North America, and overwinters in central America and the West Indies.
Male and female pairs team up to build a complex nest from plant materials like grass, moss and pine needles. Females often gather aquatic plants to bind the nest together, while males gather feathers which they procure during fights. Feathers help to insulate the nest, making it nice and toasty for egg incubation.
For more information, check out: https://animalia.bio/tree-swallow
4. Black-necked Stilt
The majestic Black-Necked Stilt, with its long, bright pink legs and narrow black bill, can be found in the Americas. This species is a shorebird and can be found along saltmarshes, mudflats, and flooded areas. The only bird with longer legs in proportion to their body is a flamingo! The Black-Necked stilt is called Aeo in ‘Ōlelo Hawai’i (Hawaiian language) which translates as ‘one standing tall’. It uses its elegant long legs to pick carefully through mud and silt, in search of insects and crustaceans.
Although it is fairly common across the Americas, the population in Hawaii is declining due to habitat loss and hunting pressures. However, this species is adaptable and can be seen inhabiting artificial habitats like dikes and sewage ponds.
For further information see here: https://www.allaboutbirds.org/guide/Black-necked_Stilt
5. Eurasian Oystercatcher
Another great example of a shoreline bird, the Eurasian or Common Pied Oystercatcher can usually be found wading along beaches and mudflats. The largest population is found in Europe, particularly northern Europe including Scandinavia.
Misleadingly, the main shellfish species it preys upon using its strong orange bill are not oysters but mussels and cockles. In fact, it can also specialise in digging up worms rather than prising open shellfish. The bill shape of an individual can tell you which technique it specialises in (a technique it learnt from its parents – a family trade passed down the generations!):
- Broad bill tips – specialises in prising open shellfish
- Pointed bill tips – specialised in digging up worms
Find out more here: https://ebird.org/species/euroys1/
6. Black Skimmer
A wonderful, eye-catching species straight from a fantasy novel, the Black Skimmer sports an over-sized, bright orange bill. Unusually, the lower section (mandible) is longer than the upper mandible and they are the only birds with this characteristic. The bird flies along, skimming over both freshwater and seawater with its lower mandible, catching small fish and aquatic insects.
Black Skimmers can even hunt at night, using their sensitive beak to seek out fish when they cannot see them. When they are not hunting, they can be seen in large flocks on sandbanks along estuaries, large rivers, and coastlines primarily in South America, but also along the southern coasts of North America.
Find out more via this link: https://animalia.bio/black-skimmer
The Razorbill is a smart-looking black and white bird, with a sharp, chunky bill and distinctive thin white lines on the bill and close to the eye. This species nests on coastal cliffsides and sea stacks in vast numbers, often mixed in with other cliffside species such as Kittiwakes and Guillemots.
At only around 20 days old, the chicks will leave the nest in a terrifying leap of faith, plunging off cliffsides and aiming to land in the water. Their flight feathers are not yet fully developed so they must take a chance to join the parents in the sea and learn how to forage before learning how to fly.
The oldest known individual Razorbill is thought to have been 41 years old at the time of sighting! It was tagged as a chick in 1968 on Bardsey Island (Wales, UK), and spotted there again in 2009.
More information can be found here: https://www.allaboutbirds.org/guide/Razorbill
8. Atlantic Puffin
The magnificent orange, black and yellow patterned bill makes a Puffin instantly recognisable. They struggle to fly with short, stumpy wings, but when they dives underwater in search of fish the wings act as flippers and propel them along. Puffins breed in colonies on cliffsides and on rocky islands or outcrops throughout the North Atlantic. However, they are rarely seen on land and spend much of their time out on the open water.
Like many seabirds, they use a special preen gland to spread oil onto their feathers which helps to waterproof them and adds to their buoyancy whilst bobbing on the ocean. Unfortunately, due to multiple threats including increased predation from gulls and introduced species like rats, contamination from pollutants, declining food supply and climate changes, this species is classed as Vulnerable by the IUCN (International Union for Conservation of Nature).
You can find more information here: https://animalia.bio/atlantic-puffin
9. Little Auk
From one cute-looking bird to another, the Little Auk or Dovekie is a waterbird and has been compared to a floating football when bobbing on the water! Although tiny, these birds are highly resilient and survive in the high-Arctic, breeding primarily in Greenland, Svalbard and Baffin Island (Canada). Little Auks mainly feed on crustaceans in both inshore and offshore locations, and can dive very deeply to access nutritious zooplankton.
They nest and breed in screes (unvegetated areas of rock), laying just one pale blue egg in rocky crevices. This species has been an important source of food and clothing material for people native to Greenland due to its abundance and how easy it is to capture on land.
If you would like to find out more: https://www.allaboutbirds.org/guide/Dovekie
10. Rockhopper Penguin
Last but certainly not least, the Rockhopper Penguin. Almost every species of penguin is black with a white belly, so it was a big challenge to choose just one! The Rockhopper Penguins species complex includes a few subspecies:
- Northern rockhopper penguin (Eudyptes moseleyi) – islands in the southern Atlantic Ocean and southern Indian Ocean.
- Southern rockhopper penguin (Eudyptes chrysocome) – further divided into two subspecies:
- Southern rockhopper (Eudyptes chrysocome chrysocome) – Falkland islands, southern Chile and Argentina.
- Eastern rockhopper (Eudyptes chrysocome filholi) – some South African islands, and subantarctic islands around New Zealand and in the Indian Ocean.
All Rockhopper Penguins feed primarily on krill but can also hunt for squids and crustaceans, spending a number of months out in the open sea. During the breeding season they can be found on rocky shorelines, inhabiting nests and burrows in grassy tussocks.
Like all penguin species, Rockhopper Penguins are highly threatened by many factors including climate change, disease, pollution, habitat loss, reduction in food supply due to commercial fishing.
Find out more about penguins and how you can support these amazing species here: https://www.birdlife.org/birds/penguins/