Speckled Mousebird

BirdAfrica

Aug 28

Written By Alexander Julius Jensen

Colius striatus

The speckled mousebird hangs belly to belly with others in its flock to keep warm while sleeping. After a meal — of toxic plants, clay, dirt, and peddles — a mousebird may hang upside down, exposing the black skin of its belly to the sun in order to warm up and aid digestion.

A Dumpy Bird

The speckled mousebird manages to simultaneously look both elegant and unabashedly goofy. Its brown-grey plumage is speckled with fine barring around its chest, throat, and cheeks. A whispy, hairlike crest sits atop its head, which often gives it a scruffy or dishevelled appearance — like it just woke up. Its beak is short and curved, with mismatched mandibles; the upper black and the lower white, like a misshapen yin-yang symbol. The mousebird's body is somewhat dumpy but is balanced by its extensive, straight tail feathers, which make up about half of the bird's entire length.

When taking to the air, the speckled mousebird is far from elegant or graceful, as its wings struggle to provide lift for its portly body and long tail. It rapidly beats its wings, tottering from side to side as if about to fall over, and then it briefly flutters through the air before landing awkwardly onto a bush or tree. It is here, amidst the branches, where its movements are most deft. A mousebird moves like an acrobat through bushes and trees, clinging to branches with its strong feet and decurved beak, scampering through the foliage like a mouse through grass.

A Dubious Diet

The mousebird's habitat is typically arid and its pickings meagre. It lives throughout the savannahs, woods, and scrublands — occasionally entering towns to forage through parks and gardens — across much of Sub-Saharan Africa. Its diet is mostly fruits, both ripe and not, supplemented by leaves, buds, seeds, aloe nectar, and some insects. Several plants that it eats are actually toxic. However, the bird neutralises their effects by ingesting clay and dirt. It must eat around its whole body weight of these low-calorie, high-fibre (potentially toxic) foods every day, which can make digestion a lengthy chore. To assist with this, the mousebird also swallows peddles that grind down the food in its belly. This gut-churning combination of high volume and fibre, toxins, dirt, clay and peddles is what gives the mousebird its characteristic pot-bellied appearance.

Friendly Flocks

Many birds around the world gather in flocks — cormorants soar above the water in militaristic V-formations, flamingos flamboyantly tiptoe in unison across shallow lakes, and murmurations of over a million starlings dance through the skies, blocking out the sun — but few flocks are as intimate as a flock of speckled mousebirds. Flocks of 7 to 8 mousebirds live together all year round, even during their breeding season, when most other birds become too temperamental for flock-living. They go about their daily foraging together, dust-bath together to get rid of parasites, and cluster together when they perch and rest — all the while keeping constant contact with “chew-chew” calls. They alert each other of any dangers; emitting a “shriek” if a ground predator is spotted or a loud “pit” if the danger comes from above. Upon hearing an alarm, the mousebirds dive for thick bushes, where they remain motionless until the danger passes, but, if the predator is persistent, the mousebirds plop to the ground and stealthily scurry away.

As night falls, mousebird families fly in single file to their roosting spots, where flocks of more than 20 birds may gather. During the night, their arid habitats can drop to chilling temperatures and, with their low-calorie diets providing little energy, the birds must cooperate to stay warm. With no sun out to warm their bellies, they instead use one another; hanging from branches in clusters with their bellies touching to share their heat. Non-breeding birds help parents incubate their eggs at night. If a flock is large enough, the mousebirds may sleep crowded together, with as many as 28 birds huddled like a feathery ball. If the night becomes exceedingly cold, the mousebirds may even go into torpor, reducing their metabolisms by up to 90% to conserve energy. Although they are now defenceless to attacks, the mass of their huddled bodies likely scares off any potential predators.

The Once-Many Mousebirds

Clockwise from top left; blue-naped mousebird (*Urocolius macrourus*), red-backed mousebird (*Colius castanotus*), white-headed mousebird (*Colius leucocephalus*), and red-faced mousebird (*Urocolius indicus*).

The speckled mousebird isn't the only species of its kind. In fact, mousebirds make up an entire bird order; the Coliiformes. Unfortunately, only six living species of mousebird remain — "living fossils", remnants of what was once a much more diverse order of birds during the early Paleogene and Miocene (~65 to 23 million years ago).¹ The six extant species are all residents of Sub-Saharan Africa and are recognizably related, sharing several similar traits; they are small — usually no longer than 35 cm (14 in) including their very lengthy tail feathers — with portly bodies, small bills, and poofy head crests. They do have their differences, however, and while the speckled is the most widespread, it is perhaps also the most plain-looking

The red-backed mousebird is the least seen of the six, likely because of its restricted range in the savannah and woodlands of Angola — where it is known as the "rabo-de-junco” or "reed-tail". Its back isn't as red as its name would suggest, but it does have a rufous tinge, and its most distinguishing characteristic is its dark face, mottled with small white dots. The white-backed mousebird of southern Africa, with its uniform grey plumage, may look a bit boring, but hidden on its back, beneath its wings, is its distinguishing pattern; a black patch, bisected by a white stripe that runs down to a reddish patch on the bird's rump. The white-headed mousebird of eastern Africa counterpoints its grey body with a pale-white head, silver beak, and zebra-like barred pattern along its back. The red-faced mousebird, also from the south, exhibits bright red, naked skin stretching from its beak to around each eye, and a more slicked-back head crest. Finally, there is the blue-naped mousebird — which lives across the dry regions of East and West Africa, as well as ranging into the Sahel — and looks much like the red-faced, with bare red skin around the eyes, but differentiated by a conspicuous blue patch at the back of the head.

Like the speckled, other mousebirds live in flocks and are exceedingly social. Together, they scurry through bushes and trees like mice in search of fruits, berries, and buds, using flexible feet and strong claws to acrobatically grip branches. The six living species may be the last of a once-great mousebird order, but, thankfully, they are all considered to be of 'least concern' — not currently in any danger of extinction.

Clockwise from top left; red-legged seriema (*Cariama cristata*), kagu (*Rhynochetos jubatus*), sunbittern (*Eurypyga helias*), and common loon (*Gavia immer*).

Bird Orders: Largest and Smallest

¹ To understand just how far the once abundant order of mousebirds has dwindled, the currently largest avian order — Passeriformes, or perching birds — has almost 6,500 extant species, while Psittaciformes (parrots) has around 400 species, and Columbiformes (pigeons and doves) has over 300 species.

Granted, there are also bird orders with fewer living members than the mousebirds. Ratites are the most striking examples. This group of (mostly) giant, flightless birds are found worldwide and only a few living species represent each order: the kiwis of New Zealand (order Apterygiformes) have 5 species, the emu and cassowaries of Australia and New Guinea (order Casuariiformes) have 4 species, while the ostriches of Africa (order Struthioniformes) and the rheas of South America (order Rheiformes) have only two species each. Other orders of ratities once existed, but are now extinct, such as the moas of New Zealand (order Dinornithiformes), of which we know 9 species, and the elephant birds of Madagascar (order Aepyornithiformes), of which we know 3 — one of which, Aepyornis maximus, is likely to have been the largest bird to ever live; standing over 3 metres (10 ft) tall.

Flamingoes (order Phoenicopteriformes), just like the mousebirds, only have 6 species, with four in the Americas and two in Afro-Eurasia. Loons (order Gaviiformes), dagger-billed water birds named for their awkward walk, have only 5 species. The mesites (order Mesitornithiformes) of Madagascar, small flightless or nearly-flightless grouse-like birds, have only 3 species — all of which are 'vulnerable'. So do the tropicbirds (order Phaethontiformes); pelagic white seabirds with long streaming tail feathers and feeble legs (which don't allow them to walk upright on land), that spend their lives soaring above the oceans. Seriemas (Cariamiformes) are an ancient order, with the earliest members dating back some 63 million years and believed to be closely related to the 'terror birds' (family Phorusrhacidae). Two species remain; long-legged and large — almost 1 metre (3.3 ft) long — terrestrial predators of South America's grasslands and forests. The order Eurypygiformes contains two disparate bird species from two disparate parts of the world. The sunbittern is a heronlike bird from the Americas, which spreads its wings and tail to reveal the patterns of a dazzling butterfly. The kagu, on the other hand, has uniform pale-bluish plumage with black barring on its wings. Endemic to the South Pacific island of New Caledonia — where it is also the national bird — the kagu is endangered and flightless, instead strutting around like a fashion model with a tall, feather crown.

Top to bottom; cuckoo-roller (*Leptosomus discolor*) and hoatzin (*Opisthocomus hoazin*).

Finally, there are the bird species so utterly unique that they alone occupy an entire order. The cuckoo-roller is the sole species in the order Leptosomiformes. Its orange legs look too little for its body while its head looks wholly too big. Its eyes appear to be placed too far back in its face and patterned in such a way as to give it a mime-like appearance. It is a native of Madagascar and the nearby Comoros Islands. Perhaps the strangest bird alive today is the hoatzin — the only species in the order Opisthocomiformes. Its proportions are the inverse of the cuckoo-roller; a hefty body with a too-small head; a head which bears a bright blue face and feathered mohawk. As it scrambles through the mangroves and marshes of the Amazon, it looks to have come straight from the Cretaceous (one nickname for it is "reptile bird"). Young hoatzins cling to trees with functioning claws, found at the end of each wing — a feature that adults lose. They use these to flee from predators, but if a climbing escape fails, they simply drop into the water below and swim to safety. The hoatzin may look fiercely raptor-like, but its diet is almost exclusively leaves — only 3% of all birds eat leaves regularly, but the hoatzin eats little else. To digest this cellulose-rich salad, the hoatzin has essentially become a ruminant, allowing food to ferment before it enters its stomach — like cows, sheep, and deer do. Its habit of fermentation, with food taking up to 45 hours to pass through its system, bestows upon it its other nickname; "stink bird". The smell of a hoatzin is said to be that of fresh cow manure and sweet hay.

**Where Does It Live?**

⛰️ Prefers forests and savannah, but will visit any habitat apart from deserts and rainforests.
📍 Ranges widely throughout sub-Saharan Africa.

‘Least Concern’ as of 01 October, 2016.

IUCN

Size // Small
Wingspan // N/A
Length // 30 - 36 cm (12 - 14 in) with about half of that being tail
Weight // 50 - 55 grams
Activity: Diurnal ☀️
Lifestyle: Social 👥
Lifespan: 8 - 10 years
Diet: Omnivore
Favorite Food: Fruit (both ripe and unripe) 🍇
Class: Aves
Order: Coliiformes
Family: Coliidae
Genus: Colius
Species: C. striatus

This bird's diet is...unique. Its favourite food is fruit, both ripe and unripe. It also eats other parts of plants including the leaves, buds, seeds, and nectar. Several of the plants that it eats are toxic — to neutralise their effects, it has to ingest clay and dirt.
Every day, it must eat about its entire body weight in these low-calorie, high-fibre (potentially toxic) foods. To aid in digestion, it hangs with its belly facing the sun, warming it up, and swallows peddles that grind down the dubious foods.
The speckled mousebird isn't a graceful flier, but it can scamper amidst branches like a mouse through the grass.
This mousebird has different alarm calls for different dangers; emitting a “shriek” if the danger is on the ground or a loud “pit” if the danger comes from the sky.
It hides from predators by staying motionless among the branches of a bush or tree, but if that fails, the mousebird drops to the ground and scurries away.
Flocks of 7 to 8 mousebirds (and sometimes more than 20) live together all year round, even during their breeding season, when most other birds become too temperamental for flock-living. They communicate with constant contact calls (“chew-chew”).
To keep warm at night they sleep belly to belly, or, in large flocks, in tight balls of bodies. In extreme circumstances, a mousebird can go into torpor, reducing its metabolisms by up to 90% to conserve energy.
The mousebirds make up an entire bird order, the Coliiformes. They were once more abundant in the early Paleogene and Miocene (~65 to 23 million years ago), but now only 6 species, including the speckled, remain.