Question

Which one or more of the following is/are signalling mechanism(s) that birds are known to use to beg their parent for food?

• A. Playing dead
• B. Vocalisations
• C. Fluttering of wings
• D. Mouth gape and colouration

Hint:

Think about which behaviours are actually directed at a parent bird to solicit food, versus a behaviour used to avoid predators.

Answer 1

The Correct Option is B, C, D

Step 1: Understanding the Question.
Nestling and fledgling birds cannot forage for themselves and depend on their parents to bring food. Begging is the set of signals a chick sends to the parent to say "feed me" and to compete with siblings for that food. We need to pick out which of the four listed behaviours are actually used as begging signals.

Step 2: Key Concept.
Begging behaviour in birds is a classic example of an honest (or exaggerated) signal used in parent-offspring communication. Known begging signals include loud calling, physical movements that draw the parent's attention, and visual displays inside the mouth that stand out against the nest background. Playing dead, by contrast, is an anti-predator or defensive tactic used in an entirely different context, not a food-solicitation signal.

Step 3: Detailed Explanation.
Option (A): Playing dead. This is a defensive behaviour, sometimes called thanatosis, used by some animals to escape a predator's attention by appearing lifeless. It has nothing to do with asking a parent for food, so it is not a begging signal.
Option (B): Vocalisations. Chicks of most bird species give loud, repeated begging calls when a parent arrives at the nest, and the intensity of these calls often signals hunger level. This is one of the best documented begging signals, so (B) is correct.
Option (C): Fluttering of wings. Chicks commonly flap or flutter their wings while begging, which both draws attention and can signal vigour or need. This is a well recognised begging display, so (C) is correct.
Option (D): Mouth gape and colouration. Many nestlings open their mouths wide, and the inside of the mouth, or the gape, is often brightly coloured (such as red, orange or yellow), which makes it a highly visible target for the parent to aim food into. Gape colour and size can also signal the chick's condition. This is a well known begging signal, so (D) is correct.

Step 4: Final Answer.
Vocalisations, wing fluttering, and mouth gape with colouration are all genuine begging signals, while playing dead is not, so options (B), (C) and (D) are correct.
\[ \boxed{\text{(B), (C) and (D)}} \]