Zygodactyl, with rotatable digits: Four digits, with the outermost two rotatable forward and backward
Swifts
Palmate
Anisodactyl, with partial webbing: Three toes forward, one toe back, three digits webbed
1st toe is backward
Webs may reach to the edges of the digits
Ducks, geese, swans, gulls
Semipalmate
Anisodactyl, with partial webbing: Three toes forward, one toe back, three digits webbed
1st toe is backward
Webs are smaller, only reaching halfway through the digits
Plovers, sandpipers, grouse, chicken
Totipalmate
Four digits webbed
Cormorants and pelicans
Lobate
Anisodactyl, with partial lobing: Three toes forward, one toe back, three digits edged with lobes
Grebes and coots
Raptorial
Long, strong digits with talons
Talons are heavy claws
Hawks, eagles, falcons
Bird Rostrum
Also known as bills and beaks
Horned;
Multipurpose, and comparable to use of human hands and fingers:
Grooming;
Feeding young;
Probing for food, catching and killing prey, and preparing food (cracking nuts, filtering particles, scooping fish, etc.);
Ripping and tearing flesh, chiseling, and manipulating objects;
Fighting and communicating.
Shapes are dependent on diet, with variations for nectar, seeds, fish, insects, invertebrates, different habitats for prey, etc. Various phenotypes are extant:
Crackers
Shredders
Tweezers
Raptorial
Probe
Spear
Strainers
Hummers
Chisels
Raptorial
Curved;
Used to cut and tear flesh;
Hawks, owls
Probe
Thin and long;
Able to sense pressure changes and detect movement of prey;
Medium length, thin, with large ability to separate
Picks up seeds and/or insects;
Tending to have “whiskers”/“bristles” around the bases of bills that catch and capture prey; “rictal bristles”
Blackbirds, Black Phoebes, Mountain Bluebird
Strainer
Large and flat;
Water passes through beaks and is collected in lamellae;
Ducks, water birds
Hummers
“Dip and sip”
Medium length, thin;
Bills sheath tongues;
Hummingbirds
Chisels
Medium, with medium thickness;
Cuts and gouges into wood and collects prey within wood;
Woodpeckers
Bird Vision
Extraordinary; many birds active in day or night
Sensitive to UV and magnetic fields;
Night birds rely on sound and light (moon/starlight); discerning shapes and movement;
High numbers of rods and cones; able to perceive smaller, imperceptible movements and figures with twice the number of rods and cones in humans;
Sensitive to magnetic fields due to cryptochrome pigments;
Maintain clear vision at high speeds.
Flat, not spherical, eyes, similar to reptiles
Specialized muscles can change eyeshape quickly
Pecten: A specialized collection of blood vessels that replenish the retina
Eyes are relative to size of head
Sclerotic ring: a circle of bony plates around the eye that embeds it rigidly on the skull of the bird
Nictitating membrane: a clear membrane/third eyelid across thee eye that lubricates and cleans the eye
Nesting Behavior
Nests are created by either one or both parents
Purpose: protects eggs and juveniles; sometimes used for roosting
Externally made from… mud, sticks and twigs, grass, rushes, reeds, moss, leaves, and lichens
Internally made from… down feeathers, hair, moss, and spiderweb silk
Different nest shapes/types are made by different groups:
Raptors make platform nests;
Passerines make cup-shaped nests;
Wrens and magpies make domicile, ball-shaped nests;
Swallows and martins make mud nests;
Blackbirds and bushtits make hanging nests;
Migratory Behavior
Migration: The ability to fly across great distances for food and shelter; may involve flight across hemispheres, across land/sea, across altitudes, or across habitats
Many birds have breeding ranges for the spring/summer and another range in the winter
Observed via range maps
Clades & Phyla
Raptors
Name derives from raptus: “one who seizes”
Diurnal predators; birds of prey
Keen senses:
Excellent hearing and reliance on sound and vision to pinpoint prey and alarm calls
Binocular vision with eyes specifically rotated towards the front of their head
Eyes are large and relative to head size
Lenses are flattened and placed far away from retina; produces a large “focal length” and image resultant
Vision is a minimum 3, up to 6 times more detailed than human eye
Increased number of “cones” or “rods” (dependent on day orr night behavior), as well as color pigments
UV sensitivity and greater color perception
Strong feet with talons; feet are specialized for grasping prey
Hooked bills.
Sexual communication via the cere: a brightly-colored, waxy structure with nares on the base of the bill
Predates many forms of prey: worms, insects, crustacean, fish, frogs, reptiles, mammals, and other birds; some specialize in prey
Most regurgitate pellets made from hair and bones of prey, which are inedible; helps identify prey of raptors
Reverse peristalsis: produced by raptors, owls, grouse, kingfishers, waders, gulls, nightjars, swifts, shrikes, Corvids, and passerines
Environmental sentinels: sensitive to bioaccumulation as end consumers
Nests in… every continent except Antarctica in various places; tundras, tropics, high mountains, and deserts;
Years-long nests are built from sticks
Platform shape nests
Nesting on cliffs, tall trees, the tops of dead snags, old woodpecker holes, ground, or burrows
Two large groups/orders are unrelated, but connected: Accipitrriformes + Falconiformes, and Strigiformes
All are protected by law; many are endangered, threatened, or of special concern, resulting of:
Habitat destruction via urbanization, deforestation, and mining;
Environmental contamination;
Collision with urban objects, or electrocution;
Shooting and trapping;
Nest disturbance.
Accipitriformes
Eagles, buteo, accipiters
Eagles are a polyphyletic grouping; accipiters and buteos have specific genera and shared characteristics
Eagles
Golden Eagle
40” long
5-7” wingspan
Colored golden, brown, grey, and yellow:
Golden on… Back, nape, and crown;
Brown on… Outer wings and tail;
Grey on… Inner wings and bill;
Yellow on… Cere;
Tail is faintly banded;
Hooked bill.
Predate mammals and birds, including prey larger than itself;
Coyotes, deer, pronghorn, fox, bighorn sheep.
Nests on… mostly cliffs, very rarely on trees
Declining due to habitat loss and shooting
Buteo
Large hawks with broad wings and tails
“Soaring” hawks that circle high in the air
Widely distributed in most habitats in California
Associated with buzzards and hawks
Red-tailed Hawk
17-22” long
43-52” wingspan
Variable colors and banding:
Distinguish via dark patagial marks on the underwing and “belly-band”;
Rufous tail.
Predates rodents, insects, carrion, and rarely birds;
Hunts by folding wings and diving down, then pinning and piercing prey
Nests in… open grasslands and woodlands.
Spends hours mid-air, stationary or gliding watching for prey
Accipiters
Hawks with short, rounded wings and long tails
Rounded wings allow the ability to dart through wooded habitats to pursue birds
Low flight with rapid wingbeats
Nests in… wooded and forested habitats
Associated with hawks and goshawks
Falconiformes
Streamlined bodies with long, pointed wings and long tails
High-speed flight for overtaking and hunting birds
Nests in… grasslands and praries; open country lands
Associated with kestrels, merlins, falcons
American Kestrel
8-10” long
The smallest falcon in the world.
20-22” wingspan
Sexually dimorphic coloration:
Unisexually… colored grey, brown, white, black, orange, and blue-gray:
Grey on… most of head
Brown patch on head
White on… most of cheeks
Black “mustache marks” underneath eyes; paired
Orange on… cere and legs
Blue-gray on… upperwing coverts of wings
Rufous patches are on the head and back
Two false eyespots on back of head create the illusion of a face; deterring predators
Crowns are dimorphic:
Brown crown in females;
Blue-gray crown in males.
Predates small mammals and birds; behavior of hovering and perching
Predated on by larger hawks and falcons
Nests in… tree cavities and woodpecker holes in open grassland habitats
Hunting Peregrine Falcon
Movement consists of plunging downward with partially closed wings;
Speeds exceed 150 mi/hr
Hunting involves striking from above with extended talons
Strigiformes (Owls)
Nocturnal birds of prey
Intense senses and adaptations regarding:
Sound →
Binaural hearing: asymmetric ear placement for sound localization
Serrations on leading edge of flight feathers: reduces noise and gives ability for silent flight
Hawk-like beaks
Anisodactyl-pamprodactyl-like talons with a flexible joint that can rotate the outer front toe to the rear
Regurgitate concentrated hair, chitin, and bone pellets as a result of carnivorous, insectivorous diet
Barn Owls
16” long
31-37” wingspan
Colored brown, white, black:
White in… face and lower crest;
Black in… eyes;
Brown in… back and sides;
Heart-shaped face.
Predates on bats, frogs, insects, and small mammals;
Reliance on hearing to hunt;
Nests in… cavities and barns in open nests
Hisses and screams
Burrowing Owl
9” long
Colored brown and white, with a barred and spotted plumage:
Brown in… plumage;
White in… eyebrow, throat, and spots/bars.
Long legs
Predates on insects and small rodents;
Nests in… rodent burrows in open grasslands
Unique behavior:
Ground dwelling, diurnal
Bobbing behavior
Endangered in many locations
Western Screech Owl
~8” long
22” wingspan
Gray plumage
Small ear tufts
Bright yellow eyes
Round head
Predates on insects, small mammals, and small birds;
Nests in… open woodlands
Calls via a series of whistles and high-pitched screeches
Water/Ocean Birds
Coastal Birds
Lives on the shores/coasts of oceans
Gulls, terns, cormorants, phalaropes, and pelicans
Cormorants
Lives in coastal waters and inland waterways: rivers, lakes, and swamps
Swims through water; diving bird
Uses spread-wing postures to dry wings, not for thermoregulation
Historically declined due to use of DDT in 1960’s
Double-Crested Cormorant
Black plumage with black-white nuptial crests, a bare, orange-yellow loral and gural skin (dark lore)
Stocky builds
Totipalmate; able to dive and swim at deep depths
Gulls/Terns
Worldwide distribution of family
Predates on different foods depending on type:
Gulls have variety: Small vertebrates, invertebrates, fish, seeds, and fruit
Terns almost-exclusively eat fish: Also consume small invertebrates (Squid, crustaceans, snails)
Nests in… coastal and inland habitats; few species are pelagic
Social birds; colonial breeding and hunting
Glaucous-winged Gull
White, gray, yellow, and reddish coloration:
White on… head and body
Gray on… mantle and primary feathers
Bill is yellow with red spots
Pink legs
Hybridizes with several other large gull species
Heermann’s Gull
Primarily colored gray and black
Dark gray body
Black on… primary feathers, the tip of the bill, and the tail
Red bill
White terminal band on the tail
Coastal-exclusive
Extremely aggressive and steal food from other birds, including pelicans
Forster’s Tern
“Bandit’s mask”: Dark mask on eyes and crest; black bill
Caspian tern
Dark crown or streaked
Thick red bill with a dark tip
Avocets
American Avocet
18” long
Black and white plumage; black on back and striped on wings
Head and neck change plumage colors seasonally
Rusty cinnamon color in summer
White otherwise
Long, pale blue legs
Dimorphic differences in bill
Unisexual long bill up-turned slightly at the ending
Male bill is longer and straighter
Prey by foraging with a side-sweeping bill
Nests on… small islands
Limits predation
Migratory, colonial species for breeding and movement
Chicks are never fed by parents
Stilts
Black-necked Stilts
~14”
Long, pink legs
Black and white coloration
Black on… bill, back, and the cap of the head crossing into the eyes
White on… lower plumage, tail, and a white spot above the eyes like eyebrows
Female back is a little more brown than black
Predates via probing mudflats and shorelines
Nests… semi-colonially on islands
Curlew
Long-billed Curlew
2’ long
Cinnamon-brown plumage that is darker on top and more orange on bottom
No dark head stripes (whimbrel); head stripes are washed out
Long, strongly down-curved bill: four times the size of the head
Forages by probing in soil
Killdeer
10” long
Colored brown, red, black, white, orange-red
Black in… double breast bands, bands on tail and head
Rusty red… on rump
Bright orange-red eye ring
Nests on open ground in gravel of open grasslands, near wetlands
Cryptic eggs; camouflaged
Broken wing act
Pelagic/True Seabirds
Lives via the ocean for all or most of the year
Penguins, puffins, auklets, petrels, albatrosses, skuas, and frigatebirds
Loons
BR-En “Divers”
Shorebirds and aquatic birds: marine, brackish, and fresh habitats
Posterior feet with totipalmate toes
Strong legs add leverage to feet
Strong fliers challenged by high wing load during take-off
Unable to walk
Majority of life is spent swimming and diving
Predate fish, crustaceans, frogs, salamanders
Nests exclusively to Western Hemisphere
Swallow pebbles for gizzard
Common Loon
Dark nape and neck with a vague white collar
Light colored bill with a dark culmen
Wading Birds
Feet adapted to walk on mud
Herons
Great Blue Heron
3-4’ tall
Maximum 7’ wingspan
Largest and most widespread heron in North America
Colored blue-gray, white, and black
Blue-gray on… majority
White on… crown of head and sides of head and neck
Black on… long plumes above the eye
Plumes of feathers on chest and back
Yellow, dagger-like bill
Predates on fish and frogs in shallow water, or mice and gophers in dry fields
Nests in… Marshes and the coasts of rivers and lakes in the Sacramento area year round
Bitterns
American Bittern
2-3’ long
3’ wingspan
Brown and black plumage
Rusty brown on top
Brown-tan white streaks on bottom breast and belly
Black stripes on the sides of throat
Predates fish, snakes, frogs, small mammals, insects
Nests in… reed-cattail platforms within the American continent
Lays 2-6 eggs in nests
Camouflages in reeds: freezes, stretches neck upward, and sways
“Pump-per-lunk” call; distinctive, sounding like water going down a drain
Anatidae
Ducks
Aquatic birds
Small stout bodies, short necks, and long, broad bills
Male coloration dimorphism
Reliance on one of two foraging strategies:
Diving ducks: Dive down and swim underwater to pursue prey
Invertebrates, fish, and vegetation
Hind-placed feet;
Submarine-like behavior;
Found in deeper water, but open with runway space;
Must run along the water surface to become airborne
Dabbling ducks: Filtering prey from shallow mud and water
Plants, algae, seeds, and invertebrates
Forward, smaller feet;
Shallow water;
Slow flight; more precise landings in small areas;
Mallards
Dabbling ducks
Northern Shoveler
Long, spatula/shovel-like bill with well-developed lamellae
Predates on small crustaceans ie Daphnia
Sieves out food particles
May feed for over an hour non-stop without moving over a meter through water
Swims with bill pointed downward
Nests in… marshlands
Northern Pintail
Dabbling duck
Long neck that constantly sits upended (up to 6 seconds non-stop underwater)
Brown, white, and black coloration
Chocolate brown on… head
White on… neck, with a stripe extending from neck upwards to head
Black on… tail feathers
Tail feathers extend into a point/pin; “pintail”
Predates on vegetation, seeds, tubers, snails
Nests in… shallow marshes and ponds worldwide
Common Merganser
Diving duck
Also known as “Goosander”
Dimorphism in head coloration
Unisex narrow red saw-billed beak
Male head is brown
Female head is rusty red
Predates on fish, crayfish, and insects
Nests in… the tree holes and crevices in freshwater rivers, lakes, and estuaries worldwide
Breeds in streams and rivers
Ruddy Ducks
Diving duck
Small ducks with blue, rust red, and black-white coloration
Distinctive broad blue bill and stiff tails
Rusty plumage
Black cap with white cheeks
Predates on aquatic insect larvae, as well as snails, crustaceans, and aquatic vegetation
Dives and sieves for food from mud up to 3’ deep
Nests in… grass debris and tufts in dense, vegetated freshwater marshes, open lakes, and ponds
Native to Americas; introduced to England
Redheads
Diving duck
Multicolored coloration:
Tricolored bill: Mostly pale blue, with a narrow white ring and a black tip
Distinctive red head
Black breast and gray back
Predates on aquatic vegetation, crustaceans, snails, and insects
Nests in… concealed rushes and cattails in shallow waters of large, vegetated marshes, lagoons, and bays exclusive to North America
Parasitic behavior; will lay eggs in other Redheads’ nests
Bufflehead
~1’ long
Smallest diving duck
White, iridescent, and black coloration
Large puffy head that is iridescent green and blue
Large white patch on back of head
Predates on insects as well as invertebrates and aquatic vegetation
Nests in… tree cavities and woodpecker holes exclusive to North America
Prefers lakes or ponds nearby mixed conifer and deciduous woodlands
Wood Ducks
Perching duck
Widespread duck in North America; cross-coast and on American continent
Sometimes migrates to Cuba in winter
Nests in hollows, tree cavities, and old woodpecker holes as high as 65’ in air, without risking damage; small ponds and rivers in dense woodland area
Unisexual features
Bright white throat and curves of cheeks
Pointed tail
Male dimorphism
Bright green crest onto the neck
Yellow flanks
Iridescent colored back
Females are brown with a teardrop-shaped eye patch
Highly precocious ducklings
Geese
Large, thin bodies white lengthy necks and short bills
Only found with brown, black, or white plumage
Swans
Large bodies and long necks
Short legs
White, with some black coloration
Coots
American Coots
Closer related to rails and cranes than to ducks
Lobate; more efficiently walk on mud, swim, and release heat in summer
Predates on aquatic vegetation, fish, frogs, crustaceans, snails, worms, and aquatic insects
Nests in… similar habitats to ducks: freshwater lakes, ponds, rivers, and marshes
Found in large flocks with up to hundreds of individuals
Perching Birds
Anisodactyl feet adapted to perching on branches
Sit and sleep while perching; clutch to perch with tendons
Commonly known as Passerines
Represents more than half of all bird species (over 6,000 of 10,000 extant bird species)
Most are singers, are brightly colored, and/or highly migratory
Nests in… cup-shaped nests
Passeriformes
Corvids
Steller’s Jay
Black and blue coloration
Black on… head, back, crest, bars on the tail
Blue on… bars on the forehead, wings, tail, belly, flanks, and undertail
Variance: Southern Rockies Steller’s Jays have white forehead streaks
Nests in… preferably moist mixed oak/conifer forests on the Sierra Nevada and coastal range, or Rockies range to Pacific Coast; considerably higher range/elevation
California Scrub-Jay
A part of Western scrub-jays: vs. the Woodhouse scrub-jay (darker breast with blue undertail coverts, and living on the east interior region)
Blue and white coloration
Blue on… head, wings, tail, breast band
White on… supercilium, throat, belly
Northern Californian white undertail coverts
Black on… face and auriculars
Predates on insects and oak acorns; sometimes takes eggs
Caches acorns for winter
Nests in… woodlands and chaparral from West (Washington through California)
Yellow-billed Magpies
Black and white, iridescent, and yellow colorations
Black on… bodies, head, backs, wings, and tail
Iridescent green on… tail and wings
White on… large patch of wings and belly
Yellow on bill, and on a patch of bare skin around the eyes
Colonial, communal behavior; collectively retribute against predators via mobbing; highly social
Endemic to California; restricted to foothills and Central Valley
Domicile, cup-shaped nests
American Crows
17-20’ long
Dark, glossy black plumage
Straight bills and square tails in flight
Ravens have a wedge-shaped tail in flight
Predates omnivorously: fruits, seeds, insects, eggs, small vertebrates
Nests in… Roosts in US through Canada, and forages across high distances
Tends to flap wings in flight
Intelligent, inquisitive, and complex vernacular
Woodpeckers
Zygodactyl feet adapted to grip onto bark
Chisel beaks
Diurnal and early evening predators; roost during the night in nests
Large diversities;
Different communal behaviors: some species are solitary or asocial, and some species form large communal groups
California has 14 species of woodpeckers
Keystone species: Provides nest cavities for over 40 species of birds in North America
Predates on mostly tree insects
Gathers with wedged bill, muscles, and long barbed tongue
Characteristic woodpecker tongue
Long, extensible tongue that is rigid
Framed on the base of a cartilage-bone structure known as the Hyoid Apparatus
Y-shaped apparatus with two fork ends known as horns connected to the muscles and ligaments from the tongue to the head/eye/nasal cavity
Horns wrap around the skull
Horns are used to extend rigid tongue and buffer impacts
Acorn Woodpecker
Communal species
Members of a group are in an extended family related to the females except for the breeding males
Members are responsible for territorial defense, feeding young, and storing/protecting/creating acorn granaries in tree trunks, telephone poles, and old fence posts
Predates mainly on acorns, sometimes on other nuts/seeds and on insects
Protective of acorns; smaller sizes of acorns are moved to smaller holes and embedded by pounding so they are not stolen by squirrels
California Quail
Callipepla californica
State Bird as of June 1931
Unisexual: grey and brown plumages on top, brown flanks with white streaks
Male dimorphism: black face outlined by a white stripee
Teardrop-shape plume/topknot that is larger and more distinct on males
Scaled underparts
Predates on seeds, buds, and grasses; also insects, spiders, and snails
Nests in… Scrub, chaparral, and grassland habitats from Oregon down to Baja California
Ground-based prey birds
Communal families:
Explode in flight and scatter when surprised by predators
Call back together once safe via assembly calls; “Chicago” birdcall
