Geoffrey,
Your points are fair but in their defence, I suggest the difference is in the pose. The comparison highlighted by the arrow and ? is that in that picture
Cayley shows the bird’s wings lowered and under the tail but Slater shows the bird’s wings raised and over the tail. Both are correct in terms of what the bird can do. The raised wings cover the lower back because the secondaries of both wings are close enough
to fully cover the back whilst in the other the lowered wings expose the lower back.
I suspect that the intention of Cayley was simply to emphasise that in pure “white backed” forms, there is no black band anywhere from the hind neck
to the tail tip. Slater’s picture covers this. Even so, there is a big difference in the distribution of white on the upper surface of the wing in these pictures. But that is the case in the birds.
Philip,
From: Canberrabirds
On Behalf Of Geoffrey Dabb via Canberrabirds
Sent: Monday, 2 February, 2026 4:17 PM
To: Canberrabirds <>
Subject: [Canberrabirds] In search of Our Magpie, 1
A few thoughts about the magpie. This bird might prove to be useful in illustrating how we are going to sort and classify birds. A good starting point is the carefree days of
What Bird is That? The pictures stayed the same through many editions but the text was revised over the years. At first there were two species, leaving out the Western one, for the moment. Then came the ground-breaking Slater guide in 1974. Unlike
Cayley, this showed a visible gender difference in both species – the charcoal suffusion in the white nape/back of the female. The distributions of the species were understood to be much as indicated by the Slater maps. There is no reason why anyone would
compare the illustrations, but if they did they might notice differences in the way each artist treated the lower back of the ‘White-backed’. Next: another look at the taxonomy.
