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couple of questions

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A friend recently posed these questions. Does anyone have a good answer?

Tony

Both were questions asked yesterday at a course I’m teaching, and I can’t satisfactorily answer either.

1. Why are NZ birds generally less brightly coloured than east coast Australian ones?

> A couple of possible responses occur to me: > a. It’s a false premise – there are too few terrestrial native NZ species > to make a valid comparison. > b. NZ species tend to be dense forest dwellers, where colour is less > relevant in communication than in the open forests and woodlands of > eastern Australia. But since I haven’t even set foot in our nearest > Gondwanan neighbour I’m not even sure if my starting point is correct. > In any case I don’t find either response very satisfactory.

2. What is it about WA that ‘fades’ birds?! eg Yellow-tailed to White-tailed Black-cockies; Eastern Yellow to Western Yellow and White-breasted Robins.

> It’s such a small sample size that I’m forced to concede that it’s > probably coincidence, but that doesn’t satisfy me either. >

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Comments

3 responses to “couple of questions”

  1. David James Avatar
    David James

    I cannot answer to the second question posed by Tony Lawson’s friend:

      Firstly, the question is not posed in a way it can be answered. It is a question about the evolution of colour in certain bird taxa, not about WA. Really, the question is compound: “why have some species pairs/groups of birds evolved yellow forms and white forms in different geographical areas?” and “is the same reason(s) involved for robins and cockatoos?”. Answers to these will require answers to “how did each species group evolve?” and “what is the evolutionary function of the colours in each group?”. Answer these 4 questions and it should be clear whether “WA” is a causal factor in these two groups or whether it is coincidental.    Secondly, the question is based on a premise that is probably false. There are plenty of brightly coloured birds and many other colours in WA, as Frank has noted, and plenty of faded birds in the east. There is no answer to the question, “why is the sky yellow?”.   Tempting as it might be to think so, there is probably nothing in the water in WA that makes things dull 🙂     The first question presents similar problems. However, in this case I suggest that the premise is based on a biased view that Australia has brighter coloured birds than NZ does. It does, but it also has duller-coloured ones like Brown Gerygone, Brown Honeyeater, Large-billed Scrubwren, Jacky Winter, etc. These all have different evolutionary reasons for being dull in colour. NZ simply has fewer bright bird species, fewer dull bird species, fewer bird species, less evolutionary radiation of birds, less variety. Which begs the question, why….   Sent: Tuesday, 26 July 2011 4:40 PM

    Tony Lawson posed the question :

    2. What is it about WA that ‘fades’ birds?! eg Yellow-tailed to White-tailed Black-cockies; Eastern Yellow to Western Yellow and White-breasted Robins.

    I disagree.  Western Spinebill vs Eastern Spinebill.  Splendid Fairy-wren vs Superb Fairy-wren.  Red-capped Parrot vs ???  And Western Rosella and Red-eared Firetail hold their own. _________________________________________________________________ Frank O’Connor           Birding WA http://birdingwa.iinet.net.au Phone : (08) 9386 5694              Email : foconnor@iinet.net.au ===============================

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    David James, Sydney burunglaut07@yahoo.com ============================== ===============================

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  2. Sonja Ross Avatar
    Sonja Ross

    I wonder if Q2 is anything to do with the amount of hot sunlight the birds have been exposed to over a long time. For example, compare the summer Perth had compared to the summer on the east coast.

    Sonja Ross

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  3. brian fleming Avatar
    brian fleming

    NZ birds are less colourful than Australian ones – why? A guess – far fewer species so far less need to be distinctive. In Australia we have four Petroica Robins (Scarlet, Flame, Pink, Rose) in the east. Some of these overlap with others in habitat – therefore bright distinctive colours may be required in territorial males.

    In NZ there are only two Petroica sp – the Tomtit (yellow breast S.Island, white in north) and the Robin – basically grey all over. (The Chatham is Black Robin is black and a long way offshore).

    I had a heated discussion with an English tourist about Mallards and Black/Grey Ducks, while observing mongrel hybrids in Christchurch. As she believed that ducks could not interbreed unless they were the same species, and therefore that the local Grey Ducks had ‘deteriorated’ by losing bright male colouring, she thought the introduction of Mallard to ‘give them back their correct colours’ was a Good Thing. When we were in NZ we saw only 2 pair of true Grey Duck on a very isolated South Island lake. Everything else was a Mallard/Grey hybrid.

    Anthea Fleming

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