House sparrow (female), Passer domesticus
A contender for the commonest wild bird
title. Originating in Europe house sparrows are found across
2/3rds of the worlds land surface.
used permission of David Friel
Blue-eyed shag, Phalocrocorax atriceps
The blue ring is surrounding the eye, it
is not the iris, the yellow wattle develops during
the breeding season
Snow petrels, Pagadroma nivea,
Courtship behaviour, the female out in
front leads the male who must prove himself by following her
aerobatics that often take place close up to cliff faces. In
a relatively calm moment, the male is calling to her.
Male red-billed quelea, Quelea quelea
Another contender for the commonest wild
bird title. Found in sub-Saharan Africa, there are estimated
to be 1.5 billion of these small birds, though other figures
have put the number at up to 10 billion. They are regarded as
being a significant pest as huge flocks can settle on and decimate
crops grown for human food.
picture used permission
of New Jersey Birds
Adelie penguins, Pygoscelis adeliae
these are probably two males rather than being
a breeding pair. Penguins usually mate for life, these are on
the sea-ice in Antarctica early in the spring, the males arrive
first and make a nest for the later arrival of the female. They
often travel together whether on ice or sea.
Pelicanus occidentalis urinator
A typical pelican, this one was
photographed in the Galapagos
Magnificent Frigate birds,
This group are heading out to sea to go
fishing in the Galapagos Islands. The ones with white under-bellies
are female, while the darker ones are male. These are large
birds with up to a 2.3m wingspan.
Ostrich, Struthio camelus
Native to Africa where it is widespread,
the ostrich is the largest bird, lays the largest egg and runs
faster than any bird at up to 70 kmh (43 mph)
Aves is a Class in the Subphylum
Vertebrata of the Phylum
Chordata, so they have all of the characteristics of both of
these groups in addition to the following:
Kingdom - Animalia
- Waterproof skin covered in feathers
- Endothermic, warm blooded
- Hard shelled eggs that are
waterproof (cleidoic - closed egg)
- Beak or bill rather than teeth
- Bipedal (walk on two legs
- Forelimbs developed into wings
- Most members are highly adapted
for flight with forelimbs modified
as wings and many weight saving features such as hollow
Phylum - Chordata
Subphylum - Vertebrata
Class - Aves
There are more
species of birds than of any of other the vertebrate classes.
They are found worldwide from the deep Arctic to the deep Antarctic
and all stations in between. The fact they can fly in and fly
out again means that they are able to make short visits to many
places to take advantage of seasonal food supplies in a way
that other animals can't. They are able to make use of what
otherwise would be very harsh environments if they stayed year-round.
Birds are the most recently evolved of the vertebrate classes,
with the oldest fossils going back about 160 million years.
They are considered to be the modern descendants of the dinosaurs,
being the only direct evolutionary line that survived the extinction
event that wiped out all the other dinosaurs about 65 million
The group includes:
Possibly more than any other animal group, the birds are
the easiest to identify and the least likely to be mis-identified.
The combination of the obvious characteristics of bipedalism,
a beak and feathers is unmistakable. There
are around 10,000 species of birds arranged in 29 orders, some
examples are given here:
- Anseriformes - waterfowl,
web-footed for swimming - ducks, geese, swans
- Apodiformes - "footless"
in Latin (they do have feet though), legs are used for perching and have no scales
as other birds do - swifts, hummingbirds
- Cathartiformes - large scavenging
birds, usually have a bald, featherless head -
vultures or condors
- Charadriiformes - usually
found around water, frequently the sea -
gulls, auks, plovers
- Columbiformes - the only
birds capable of drinking by sucking without having to tilt
the head back, able to produce "crop milk" to feed the
young - doves and pigeons
- Falconiformes - raptors,
sharp hooked beak, strong legs and feet with strong claws
- falcons, eagles, hawks
- Galliformes - fowl, ground
feeding, heavy bodied birds, usually able to fly but only
for short distances, walk to get about -
grouse, pheasant, ptarmigan
- Opisthocomiformes - young
possess claws on two of their wing digits (fingers), a very
primitive feature - a single species the
- Passeriformes - songbirds
or perching birds, usually smallish birds, more than half
of all bird species are in this order -
sparrows, crows, drongos, birds of paradise, larks, swallows
- Pelecaniformes - water birds
that feed on marine life, webbed feet, some have a large
throat pouch - pelicans, cormorants, frigate birds
- Phoenicropteriformes - long-legged,
long-necked filter-feeding waders - flamingos
- Piciformes - mainly tree-dwelling,
feet have two toes forwards, two backwards - woodpeckers,
- Procellariiformes - tubenoses,
most feed in the open sea, nostrils in tubes, nasal gland
to secrete excess salt, long narrow wings, webbed feet -
- Psittaciformes - mostly
tropical and subtropical, strong curved bill, upright stance,
strong clawed feet, often bright or vivid colours -
macaws, cockatoos, parakeets
- Sphenisciformes - aquatic
flightless birds found in the southern hemisphere only as
far the equator - penguins
- Strigiformes - sharp hooked
beak, strong legs and feet with strong claws, large forward-facing
eyes in a characteristic and obvious circle of feathers,
binocular vision, the eyes can't move in the socket so the
whole head moves - owls
- Struthioniformes - ratites,
large flightless birds, no "keel" on the breastbone
(sternum) to which other birds attach their flight muscles
- ostriches, emus, kiwis
The smallest bird is the bee
hummingbird at 5.7cm (2.25in) long and 1.6g (1/18th of an ounce).
The largest bird is the ostrich
at over 2.7m (9 feet) high, weighing 156kg (345lb), this is
97,500 times heavier than the smallest bird.
The largest wingspan is that
of the wandering albatross with a measured maximum of 3.63m
(nearly 12 feet).
The commonest bird is the domestic chicken
as it is reared for food, there are around 4 chickens for every
person on earth which comes to 25 billion + chickens. Of wild
birds, the European house sparrow is thought to be the most
common being found on about 2/3 rds of the land surface. A small
songbird, the red-billed quelea is thought to be close in numbers
with a population of 1.5 billion though is confined to sub-Saharan
What do birds eat?
You would expect such a widespread and varied group as the
birds to include members that eat most things. This is
largely true, though there is one common factor to
the food eaten by birds and that is that it is high-energy.
Birds have the highest body temperatures of any animal with
the highest metabolic rate in terms of energy needed
per gram of body mass.
This means that they can't afford to waste time eating bulky low energy
foods as they wouldn't be able to be so active. It also means that they
need highly concentrated energy foods in order to still be light
enough to fly. Birds can't afford to keep food in their digestive
systems for long as the weight would soon build up and make
flight very difficult. There are no bird equivalents of cows
or sheep for instance.
As examples of the energy needed, a warbler (small songbird) might eat 80% of its own body
weight a day, while a shrike can digest a whole mouse in three
Generally speaking food from an animal source, invertebrates, fish, small mammals,
other birds etc. is more nutritious than much plant derived
Birds that do eat plant material eat the higher energy
parts such as seeds, nectar and fruit rather than leaves and
stems. Those birds that do eat leaves tend to be very selective
choosing only the most tender nutrient dense ones that are
the easiest and quickest to digest.
One herbivorous bird, the Canada Goose removes the easy to get at nutrients
from grass that it eats and then rather than further digestion to recover
more nutrients, it defecates it out and then eats fresh grass. The
faecal pellets so produced may be eaten by reindeer such is
their remaining nutritional content.
Another unique aspect of the way that birds feed is that
they have a beak or bill and no teeth, most food is swallowed
more or less whole and not chewed in the way that
other animals might. The digestive systems of birds are very
efficient with a gizzard to grind up the food and very aggressive
Birds eat fish, squid, worms, grubs, ant and termite eggs,
other birds, small mammals, snakes, lizards, frogs, toads etc.
any animal smaller than them that they can catch.
They may eat fruit, seeds, unopened flowers, young leaves,
buds, nuts, and other concentrated energy easy to digest plant
What eats birds?
Catching birds to eat is not easy because they can quickly
fly away. However while flight enables them to escape predation
it also puts them in the way of predation.
Flight requires birds to be lightweight, so when they reproduce,
they carry the young for as short a time as possible. The fertilized
egg with a very large food supply is produced. This means that
birds are tied to their nests in order to reproduce which makes
them very vulnerable to predation at this time. So what eats
- Predatory birds such as
falcons, eagles, hawks and owls eat other birds.
- Domestic cats eat birds
catching hundreds of millions a year world-wide, perhaps
- Unexpected animals like large spiders,
frogs and toads eat small birds.
- Mammalian predators such
as stoats, weasels, raccoons, jaguars, foxes, lions, tigers,
bears will eat birds especially if they can catch them on
the nest where even if they don't catch the adults, there
are likely to be nestlings or eggs to eat.
- Seals, sharks and large fish
Birds are often in the middle to the top of food chains being
both predator and prey to different animals.