Ornithology term
Altricial
Also: nest-bound
Definition
Describes young birds that hatch relatively undeveloped and depend on adults for warmth and food.
Why it matters in the field
Recognizing altricial development helps observers interpret quiet nest behavior and repeated food deliveries. It also explains why recently fledged young can remain dependent after leaving the nest.
Examples
- Most songbird hatchlings emerge with closed eyes, sparse down, and little ability to regulate body temperature.
- A nestling robin remaining in the nest while adults bring food shows the prolonged care associated with altricial young.
Common confusion
Altricial describes condition at hatching, not a bird that is sick or permanently unable to fly. A fledgling can be mobile while it still depends on adults.
Observation notes
When watching an active songbird nest from a safe distance, note whether adults carry food, remove fecal sacs, or brood unseen young. These behaviors can support an altricial interpretation without exposing the nest contents. Use a scope when possible, keep the location private, and move away if an adult gives alarm calls or delays its approach.
After young leave the nest, look for short tails, soft begging calls, uncertain movement, and adults arriving with food. These clues describe a normal dependent fledgling more reliably than flight skill alone. Never return a healthy feathered fledgling to a nest solely because it sits low or appears inexperienced; observe first and contact a licensed rehabilitator when injury is evident.
For a field report, distinguish nestling from fledgling and describe feather development, posture, movement, and adult attendance. Avoid estimating exact age unless a monitored study provides known hatch dates. Development rates differ among species, and weather or food supply can change what an observer sees. Accurate stage language is more useful than assuming that every small, begging bird has fallen prematurely.
Word origin
From Latin altrix, meaning a female nourisher.