Biology Reference
In-Depth Information
(a)
(b)
(c)
(d)
Fig. 14.8
Extravagant signals. (a) The Royal flycatcher,
Onychorhynchus coronatus
. Photo © Joseph Tobias.
(b) Bird of paradise,
Paradisaea rubra
. Photo © Tim Laman/nature/pl.com (c) The bower of a Vogelkop Gardener
Bowerbird,
Amblyornis inornata
, consists of a cone-shaped hut, in front of which is an area that is kept clear of
debris and decorated with items such as flowers, fruit, beetle wings and leaves. Photo © Richard Kirby/naturepl.com.
(d) Male superb Lyrebirds,
Menura novaehollandiae
, have an amazing mimicking ability, producing a song that is a
rich mixture of their own song and other sounds that they have heard, such as the songs of other birds, and human
noises, ranging from camera shutters to chainsaws to car alarms. Photo © J. Hauke/Blickwinkel/Specialist Stock.
Handicaps
Animal signals are often obvious to us because they are extravagant and showy. The
volume and diversity of the dawn chorus, the flamboyant feathers and dances of birds
of paradise, or the colours and sweet scents of flowers (Fig. 14.8). How could such
extravagant and presumably costly displays be favoured by natural selection? Amotz
Animal signals
can be costly and
extravagant
