another difficult question black and white colouring

["Philip A. Veerman" <>]

Why would there have been more predators, let alone "many many more predators" in the past, than the number present in the last million or so years (during which the pied appearance presumably developed)? The ratio of numbers of predator to prey (for endotherms and ectotherms) is fairly constant through time. It is one of the factors that has been used in the dinosaur endothermy debate (going back 100 million or so years). One could ask why are birds pied just as much as why are they brown. There does not need to be a reason. The most obvious birds in the open areas of Australia are black (ravens), white (cockatoos) or pied (magpies). They live very successfully in the same climate and temperature conditions, so the patterns would appear to be fairly unimportant, except for evolutionary accident setting up social signalling for homogeneity of each species.

 

Philip

-----Original Message-----
From: Mark Newton - Adelaide, SA <>
To: Philip A. Veerman <>; birding aus <>
Date: Wednesday, 25 February 2004 18:45
Subject: Re: [BIRDING-AUS] another difficult question black and white colouring

The birds mentioned make themselves conspicuous today, but during the evolution of this colour variation many many more predators would have prevailed in a very different world making camo an important trait for even the boldest creatures. 

 

Certainly an interesting question with a myriad of possible answers.

 

Cheers

Mark