1. Different kinds of development by vertebrates after birth
The two kinds of developmental strategies for birds after birth, is mainly linked to nest building, feeding and protecting from predators in their environment.
Altricial development (‘requiring nourishment’)
Precocial development

2. Altricial development
Altricial refers to species whose newly-hatched or -born youngs are helpless and require care for a specific amount of time. They …
are relatively immobile,
lack hair or feathers,
are not able to obtain food on their own,
must be cared for by adults,
have closed eyes which are common, though not always the case.
They cannot leave the nest and are fed by their parents until their body is covered in feathers and their muscles have strengthened.
They are unable to regulate their own body temperature.
(kept warm by a parent)

3. Altricial development (cont.)
Their nest are above the ground in trees or on poles to protect them from predators.
Amongst birds, for example, 
woodpeckers, owls, pigeons, etc.
Among mammals, most rodents (rat, mouse, marmot) are altricial. 
Cats, dogs, humans are
some of the best-known
altricial organisms.

4. Advantage of altricial development
With rich diet provided by parents the initial small brains developed into large adults brains – leads to greater adaptability and intelligence

5. Disadvantage of altricial development
More demanding on parents (more energy needed) for protection and feeding
Parents need to teach them to fly

6. Precocial development
Precocial refers to species in which the young
are relatively mature and mobile from the moment of birth or hatching.
They …
are able to move around soon after hatching,
are covered with down /feathers,
can leave the nest within two days,
are able to regulate their own body temperature,
Make their nests on the ground
Examples: guinea fowl, geese, ducks,
chickens, cranes, etc.

7. Advantage of precocial development
Hatchings are able to avoid predation to some extent,
They can see and run around,
Can feed themselves,
Less demanding on female/
parents once hatched – they are independent
Mother stays nearby to protect them and teach them

8. Disadvantage of precocial development
Hatchlings have relatively large brains and their brain size does not increase much
Demanding on female to produce lots of yolk so that embryo can develop into more mature chicks

9. Increasing parental care

10. ALTRICIAL DEVELOPMENT PRECOCIAL DEVELOPMENT
Some differences
ALTRICIAL DEVELOPMENT
PRECOCIAL DEVELOPMENT
Woodpeckers, pigeons, guineafowel
Chickens, duck, geese, owls
25% of yolk – less energy needed to produce
40% of yolk in egg – lots of energy needed to produce
Nests in trees, caves, on poles
Nests on the ground
Closed eyes
Open eyes
Naked very few or no feathers
Down/feathers present
Cannot leave the nest
Leave nest within two days
Cannot move around
Can move around
Cannot feed themselves
Can feed themselves
Cannot maintain their body temperature (kept warm by a parent)
Can maintain their body temperature
Parents have to protect them from predators
Parents may help to protect them
Need a lot of parental care for amount of time
Very little or no parental care