Birds are called swallows due to the unique shape of their mouths and feeding behaviors. Swallows have wide, gaping mouths that allow them to catch insects while flying. Their mouths resemble an open throat, like someone swallowing a large bite of food. This characteristic inspired early naturalists to call these birds “swallows”.
What are some key features of swallows?
Swallows have several key features that distinguish them from other bird species:
- Wide, gaping mouths for catching insects in flight
- Long, pointed wings ideal for fast, agile flying
- Streamlined, aerodynamic bodies
- Short, weak legs since they spend little time on the ground
- Predominantly insectivorous diets
- Distinctive forked or notched tail shapes
- Iridescent blue, green, and reddish-brown plumage
- Gregarious nesting behaviors with large colonies
- Migratory patterns spanning continents
These adaptations allow swallows to expertly hunt insects while in flight. Their wide mouths and flexible jaw joints let them snatch up bugs mid-air. Their pointed wings provide speed and agility to chase erratically moving insects. Swallows are highly efficient aerial hunters.
How many species of swallows are there?
There are around 90 species of swallows worldwide. They are placed in the family Hirundinidae within the passerine order. Swallows have a global distribution across every continent except Antarctica. Some of the major swallow groups include:
- Barn swallows – Common wide-ranging species with blue upperparts and reddish underparts. Found on all continents except Antarctica.
- Cliff swallows – Build gourd-shaped mud nests on cliffs and walls. Found throughout North and South America.
- Tree swallows – Smaller species that nest in tree cavities. Found across North America.
- Bank swallows – Dig nesting burrows in dirt mounds and cliffs near water. Widespread in temperate Northern Hemisphere.
- African swallows – Diverse family limited to Africa. Examples are the white-throated blue swallow, Angola swallow, and lesser striped swallow.
- Asian swallows – Group of species only found in Asia. This includes the red-rumped swallow, striated swallow, and Pacific swallow.
While distributed worldwide, the highest diversity of swallow species is concentrated in Africa and tropical southern Asia. New species continue to be identified by ornithologists as swallow taxonomy is further refined.
What are the migration behaviors of swallows?
Many swallow species are long-distance migrants that travel huge distances between breeding and wintering grounds. Some epic migratory journeys include:
- Barn swallow – Breeds across North America and Europe. Winters in Central and South America. Roundtrip of up to 18,500 miles.
- Purple martin – Breeds across eastern North America. Winters in the Amazon Basin. Roundtrip of 6,000+ miles.
- Tree swallow – Breeds across Canada and Alaska. Winters along the U.S. Gulf Coast and in Mexico. One-way trip of 3,000+ miles.
Swallows migrate in large flocks, converging in the billions along migratory flyways. They migrate to take advantage of abundant insects in the northern temperate summers. As winter approaches and food declines, they return to tropical regions. Swallows can migrate up to 285 miles in a single day at speeds averaging 22-34 mph.
Some key factors that enable swallows’ extreme migrations include:
- Ability to feed continuously on the wing to refuel
- Highly efficient, aerodynamic flight
- Innate orientations and navigation capabilities
- Ability to fly long distances nonstop over barriers like oceans and deserts
Swallows also exhibit high nest site fidelity, often returning year after year to prior breeding grounds. Their navigational skills and endurance allow them to undertake some of the most extraordinary migratory journeys in the animal kingdom.
How do swallow nests reflect their behaviors and adaptations?
Swallows build specialized nests that reflect their aerial lifestyles:
- Mud nests – Built by cliff and barn swallows using mud pellets cemented to a vertical surface. The mud cups provide a secure structure for eggs and chicks and easily attach to walls, cliffs, and beams. Allow large dense colonies.
- Burrows – Dug into dirt mounds by bank swallows. The burrows offer protection and temperature regulation. Colonies can contain thousands of individual burrows.
- Cavity nests – Tree swallows adopt old woodpecker holes and nest boxes. Cavities provide safety for their vulnerable young and are warm insulation.
Swallows may reuse and repair the same nest for many seasons in a row. Their nest placement takes advantage of their aerial abilities – allowing direct access to nests on high vertical surfaces without needing to land first. Overall, swallow nesting habits allow them to breed in large, highly protective colonies.
Cliff swallow nests
Cliff swallows build mud nests tucked under ledges or eaves of buildings. Their gourd-shaped nests have a small enclosed entrance hole at the top. The nests can be packed densely together, providing safety in numbers.
Bank swallow burrows
Bank swallows dig tunnels into steep dirt and sand banks, usually near water. Their burrows provide protection from predators and weather. Numerous burrows are clumped together in dense colonies.
How do swallows hunt and eat while flying?
Swallows have specialized hunting and feeding methods to eat on the wing:
- Aerial insectivory – Swallows are aerial insectivores, meaning they hunt exclusively on the wing. They eat flies, mosquitoes, bees, wasps, flying ants, moths, and more. Hunting from flight allows swallows to access a vast food source.
- Wide mouths – Swallows have large gaping mouths reaching back beyond their eyes. This allows them to efficiently scoop up insects mid-flight.
- Flexibility – Their jaws articulate widely at a flexible joint. This lets swallows open their mouths incredibly wide to capture erratic prey.
- Speed – Pointed, streamlined wings give swallows speed and agility during aerial pursuit of insects.
- Maneuverability – Shorter, broader wings provide excellent lift and turning capability to nimbly chase insects.
- Stealth – Silent flight from specially adapted feathers lets swallows stealthily approach insects.
Swallows combine all these traits to make them supremely effective at hunting insects while airborne. Their flying and feeding abilities are interconnected adaptations that allow swallows to thrive.
How did swallows get their name?
Swallows got their English name from the appearance of their wide, gaping mouths which early scientists thought resembled an open throat in the act of swallowing food. Some examples include:
- Latin – Their scientific order name Hirundinidae comes from the Latin word hirundo meaning swallow. This references their prominent swallowing-like mouths.
- French – The French word for swallow is hirondelle, also derived from the Latin hirundo.
- German – The German word Schwalbe translates to swallow and swoop, likely imitating a swallow’s graceful flight.
Similar names appear in Greek, Italian, Spanish, and other languages. Beyond Europe, some names translate to “bird of the sky” or “bird that flies continuously” – also nodding to the swallow’s specialized aerial abilities that so captivated early naturalists.
Conclusion
In summary, swallows got their descriptive English name from early biologists struck by their large, gaping mouths that allow efficient capture of insects during continuous flight. Key adaptations like wide jaws, pointed wings, streamlining, and aerial agility enable swallows to hunt and migrate over vast distances. Their mud nests and cavity nests reflect highly social, aerial-centric lifestyles. Globally, swallows’ supreme mastery of flight continues to inspire both their common name and scientific fascination.