### animal | vertebrate | bird:

Young bird
* Many young birds leave the nest before they have full flight capabilities
  - spend time out of the nest while learning to fly
* Most young birds are totally on their own soon after leaving the nest.
* Most young birds eat animal food
  - establish territory
  - feed on insects
  - grow very quickly indeed
* Most young birds have ability
  - beaks
  - black beaks
  - brown hues
  - calls
  - chins
  - dark eyes
  - flesh
  - tendencies
  - learn to forage for their meals
  - leave the nest well before they are able to fly
  - lose feathers
  - make sound
* Most young birds reach maturity
  - sexual maturity
  - require proteins
  - survive accidents
* Most young birds take first flight
* Some young birds become adults
  - have collars
  - learn to recognize their parents or foster parents within a few hours of hatching
  - remain with parents
  - resemble hens
  - starve to death
  - stay with parents
  - take care
* acquire adult plumage characteristics during their second year.
* are blackish green in color and have yellow streaking in the beak
  - chocolate brown, gradually turning white as they grow older
  - covered in brown markings
  - dark brown with dark eyes
  - dependent on insects for vital protein
  - duller in colouration
  - easy to identify
  - generally lighter in color
  - have brownish heads and undersides
  - largely insectivorous
  - less glossy than adults, but they lose the dullness when they reach maturity
  - more susceptible to a severe debilitating infection than are adult birds
  - most likely to be taken by hunters
  - mostly gray in coloring, with black beaks
  - overall pale-brown until they grow their adult feathers
  - precocial after hatching
  - significantly more prone to injuries than adults
* are similar in appearance to adults
  - to the hens
  - susceptible to environmental insult
  - vulnerable to chills and pneumonia
  - youngs
* bear grey and brown scalloped plumage on their backs and wings.
* become listless, pale, show ruffled feathers and appear unthrifty
  - tasty feasts for some mountain cats, martens and large owls
* begin foraging on their own somewhere between two and three weeks of age.
* deserted by their parents are most probably sick or abnormal.
* develop rapidly.
  - mainly insects, as do the young of most birds
  - mostly animal foods such as soft invertebrates
* follow, imitate and learn from their parents all summer.
* have a brownish-black bill all year
  - head and body moult about five weeks after hatching
  - speckled breast with no red and are mostly gray in appearance
  - tendency to pick at their own excretion
  - very efficient insulation against the cold
  - appetite
* have black beaks
  - legs and feet and a dark bill
* have dark eyes initially that become paler as they mature
  - darker, brownish plumage
  - grayish-brown upperparts
  - large numbers of down feathers
* have lighter legs, flexible breastbones and flexible beaks
  - soft breastbones and flexible beaks
  - red feathers scattered throughout the plumage
  - to leave the territory within two years, forced by parents
  - trouble breathing and gasp for air
  - very special diets
* hear their parents, other adults, and even territorial rivals.
* know already how to sing
  - instinctively how to hunt
* lack the black throat patch and have greenish-yelow upper parts.
* learn how to forage after they learn to fly.
* learn to recognize the markings and song of their parents right away
  - sing from their adult companions
  - talk quicker than older birds, as do solitary birds
* leave the nest after three or four months
  - in a few short weeks
  - permanently about a year later
* live in nursery flocks where they learn all skill required for independent life.
* look like females
  - similar to adults, but have gray feathers in place of the red skin on their crowns
* migrate farther than older birds.
* open beaks.
* reach maturity and join other adult birds preparing for autumn migration
* reach sexual maturity in their fourth year
* remain dependent on their parents for several weeks after fledging
  - with their parents for many months after fledging
* resemble adults, except they have gray heads
  - females, but are browner and have a paler bill
  - non-breeding birds
* seem to prefer spiders as a supplement to their diet while adults prefer berries.
* select the song of their own species out of many alien songs in their environments.
* show a lot of white on the head.
* stay in the nest three to four weeks
  - with their parents for between one and two years
* take about a year to develop full adult coloration
* tend to be darker and browner than the adults
  - take live food better than dry food
* to find food.
* vary in the shade of brown, with darker birds presumably males.