How are bird families classified?

Bird families are classified based on shared physical and genetic characteristics. There are two main systems used to classify bird families:

• Sibley-Ahlquist taxonomy
• Howard and Moore taxonomy

The Sibley-Ahlquist taxonomy groups birds based on DNA-DNA hybridization studies. This looks at how similar different birds’ DNA is and clusters them into families with other birds they are most closely related to genetically.

The Howard and Moore taxonomy uses both genetic and morphological (physical feature) evidence to classify bird families. It builds on traditional taxonomy methods but incorporates new genetic findings.

There are approximately 220 recognized bird families under these modern classification systems. Families are then broken down into smaller groups including subfamilies, tribes, and genera. Understanding how birds are scientifically classified helps us better grasp evolutionary relationships.

Main Bird Family Groups

There are around 30 main orders that bird families belong to. Some of the largest groups include:

Passeriformes – The passerines or perching birds make up over half of all bird species. Examples include sparrows, finches, crows.

Charadriiformes – The wading and shorebirds like gulls, auks, plovers.

Accipitriformes – Diurnal birds of prey such as eagles, kites, hawks.

Anseriformes – Waterfowl including ducks, geese and swans.

Galliformes – Gamebirds like pheasants, grouse, turkeys and chickens.

Columbiformes – Pigeons and doves.

Apodiformes – Hummingbirds and swifts.

Coraciiformes – Kingfishers, bee-eaters, rollers.

Piciformes – Woodpeckers and toucans.

Struthioniformes – Flightless birds like ostriches, emus, kiwis.

These provide a broad overview but there are many more orders and families within them. Now let’s look at some specific examples of major bird families.

Key Bird Families

Here are some of the best-known bird families, covering a diverse range of species:

Finches (Fringillidae)

Part of the order Passeriformes, the finch family includes many common songbirds. There are over 120 species like canaries, goldfinches, crossbills and grosbeaks. They have stout cone-shaped bills adapted for cracking seeds.

Parrots (Psittacidae)

Parrots are tropical birds known for their bright plumage and ability to mimic speech. There are over 350 species including macaws, cockatoos, parakeets and budgies. Their zygodactyl feet with two toes facing forward and two back help them grip and climb.

Hummingbirds (Trochilidae)

Found only in the Americas, hummingbirds are the smallest birds with high metabolisms and rapid wing beats. There are over 325 species including the ruby-throated hummingbird. They have long slender bills suited to drinking nectar from flowers.

Pigeons and Doves (Columbidae)

These are stout-bodied birds with small heads and slender bills. There are over 300 species including common rock pigeons and mourning doves. They drink by sucking and often feed their young “crop milk” from their throats.

Tyrant Flycatchers (Tyrannidae)

A large family from the Americas with over 400 species. They get their name from aggressively defending territories and preying on flying insects. Examples include kingbirds, phoebes, and peewee flycatchers.

Mockingbirds and Thrashers (Mimidae)

Known for their impressive ability to mimic calls and songs of other birds. There are around 35 species including the widespread Northern Mockingbird. They have long tails and legs and curved bills.

Boobies and Gannets (Sulidae)

These are large coastal seabirds adapted for plunge diving to catch fish. There are 10 species including the Blue-footed Booby. They have long pointed wings, short tails and slender pointed bills.

Hawks, Eagles and Kites (Accipitridae)

Powerful birds of prey that hunt during the day. There are around 240 species globally including sharp-shinned hawks, bald eagles and black kites. Hooked beaks and sharp talons help them seize and tear apart prey.

Herons and Bitterns (Ardeidae)

Wading birds found near water across most of the world. There are around 64 species like great blue herons and American bitterns. They have long legs, necks and bills used for hunting fish and other prey.

Identifying Features of Bird Families

While bird families encompass many species, members often share unique physical and behavioral adaptions. Some key features used to distinguish families include:

Bill shape/size – Bills tailored to specialized diets like seed-cracking finch bills or nectar-drinking hummingbird bills.

Leg and foot morphology – Wading birds have long legs, birds of prey have powerful talons, songbirds have feet adapted for perching.

Plumage – Shared colors or patterns like the bright reds and greens of parrots or the aposematic coloring of blackbirds.

Habitat and range – Related species often occupy similar environments like marsh-dwelling rails or tropical kingfishers.

Behavior – Shared behaviors and adaptations like the mimicry of mockingbirds/thrashers or cliff nesting of auks.

Anatomy – Skeletal structures, organ systems, and other internal anatomy that differentiates groups.

Genetics – Relatedness measured through DNA hybridization or sequencing that underlies modern taxonomy.

Using a combination of these factors allows scientists to accurately determine family level relationships between birds. Understanding these connections helps reveal bigger evolutionary patterns.

Major Bird Family Trees

Bird families can be visualized on scientific trees called phylogenies that model evolutionary relationships:

These represent just a portion of the full phylogenies but help showcase the branching patterns of related families. Over time, lineages split from common ancestors leading to the diversity of modern birds.

Conclusion

In summary, bird families are scientifically classified based on their genetics, anatomy, behavior, and other attributes. There are around 220 recognized families split into orders that share evolutionary histories. Some well-known examples include finches, parrots, hummingbirds, pigeons, tyrant flycatchers and eagles. While diverse, related families possess common traits adapted to their environments and lifestyles. Phylogenies model how these families branched over time from common ancestors. Understanding bird families provides insight into the interconnectedness of avian life on Earth.