PSYCH 3T03 Chapter 7: PSYCH3T03- (7) Mouth Colour is a Reliable Signal of Need in Begging Canary Nestlings
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Wednesday, February 28, 2018
Article 7: Mouth Colour is a Reliable Signal of Need in
Begging Canary Nestlings
-Model Species = Canary!
-Mouth colour signals need in nestlings; Changes in mouth colour accurately reﬂect
nestling’s state of need (i.e. more intense colour is proportional to greater need)!
-Of two birds, the one with an artiﬁcially reddened mouth was provided more food by
-Note: This paper contains “personal” communications and observations!
-Begging Display: Bright mouth colouration; Begging postures; Loud calls!
•Cons: Costly; Attracts predators!
-Begging creates a signalling equilibrium which resolves parent-oﬀspring conﬂict over
resource distribution and then, provides information on oﬀspring condition!
-Honest signalling models of oﬀspring solicitation yield three key predictions…!
•Begging intensity should reﬂect oﬀspring need!
•Parents should provision young in relation to begging intensity!
•Begging should be costly!
-Note: Past work has shown chick begging posture and calling are known to change
reliably in short-term with recent feeding experience!
-Rapid changes in mouth colour result of changes in blood ﬂow to mouth; Only
observed in species which have red/pink mouths!
-Hypotheses = Mouth colour should vary reliably with need; Parents should allocate
food in relation to nestling mouth colour!
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