Ian’s Bird of the Week – Tomtit

Tomtit (Petroica macrocephala) by IanIan’s Bird of the Week – Tomtit ~ by Ian Montgomery

Newsletter – 10/30/15

Last week we had the Snares Penguin and I made a passing reference to the locally endemic race of the Tomtit, so here is it and two of the other four New Zealand races of the Tomtit as this week’s choice. It’s called a Tit after the European Tits family Paridae which includes the North American Chicadees) but it’s not one of these but an Australasian Robin (Petroicidae), which in turn were named after the European Robin but don’t belong to its family either (Muscicapidae). The Tomtit’s closest relative is the Pacific Robin (Petroica multicolor) which in turn is very close related the Scarlet Robin of Australia.

A friend of mine who is a member of the bird of the week club but not a birdwatcher as such expressed confusion over subspecies (or races) and species, so I Googled a couple of references which might be useful: 1. a simple explanation2. Wikipedia and 3. a more scholarly one. I talk about them a lot as I’m interested in the classification of birds (taxonomy) and their evolution and biogeography (how they got to where they are) so here is a brief description.

Tomtit (Petroica macrocephala) by Ian

A (biological) species is the fundamental unit (‘taxon’) of the classification of organisms, both plants and animals. It’s fundamental in the sense that it is considered reproductively isolated (genetic differences are supposed to be such that interbreeding across species boundaries isn’t possible or at least doesn’t produce fertile offspring). From a bird-watching point of view, a species is what you add to lists, whether your life list, your national list, your annual list, your yard list, or your annual bird list… The possibilities are endless but in the competitive world of ‘twitching’, a species is as important as a referees decision about a goal or score in football or tennis.

Tomtit (Petroica macrocephala marrineri) by IanNothing in biology is ever quite so simple, so the differences between various taxonomic levels (species, genus, family, order … going up and species, subspecies going down) are really part of a continuum. At the lower levels – genus, species and sub-species – the degree of genetic separation and therefore reproductive isolation varies a lot. Some groups are particularly troublesome as apparently quite different ‘species’ have a taxonomically irritating tendency to hybridise. Among birds, the diving ducks of the genus Aythya come to mind and among plants the orchids are notorious for spreading their genes around. Subspecies or races (using the terms interchangeably) are usually geographically isolated so they don’t get the chance to interbreed and are usually sufficiently different to be identifiable in the field. That means if you’re a birdwatcher, you can make lists of them too…

Tomtit (Petroica macrocephala marrineri) by Ian

The eighteen century Swedish scientist and physician Carl Linnaeus is regarded as the father of modern taxonomy as he invented the binomial – double-name – system that is still in use today. This was a century before Darwin, so Linnaeus was concerned, lucky man, with only degree of similarity. He classified types of organisms as belonging to a genus (‘family’ in Latin) represented by the first name, e.g. Anas (Latin for ‘duck’) and a species, e.g. platyrhychos (Greek for ‘broad-billed’) to name the Mallard and distinguish it from say the similar Gadwall, Anas strepera, where ‘strepera’ is derived from the Latin for ‘noisy’. There is no linguistic rule to prevent mixing of languages but adjectival species names usually agree in gender with the genus, something of a challenge when one name comes from Greek and the other from Latin.

Tomtit (Petroica macrocephala dannefaerdi) by IanNeedless to say, taxonomists have added many levels since, but orders, families, genera and species are the most important. To accommodate races or subspecies a third name was added the binomial system making it trinomial. The first race of a species to be named is called the nominate race, and the name of the race, if any, must be the same as the name of the species. So the nominate race of the Tomtit Petroica macrocephala is Petroica macrocephala macrocephala(Petroica is Greek for ‘rock-dwelling’ and macrocephala is Greek for ‘big-headed’). Any additional subspecies described later will be called Petroica macrocephala somethingelse.

Tomtit (Petroica macrocephala dannefaerdi) by Ian

Sorry, that was supposed to be a brief description so let’s get back to Tomtits. The first two photos show the nominate race which occurs on the South Island of New Zealand. The male is black and white with a yellow breast; the female is grey-brown with a white belly. This pair was in an Antarctic Beech forest – quite Lord of the Rings – near Cascade Creek in Fiordland and both birds were busy feeding nestlings. The male has a juicy green caterpillar and a large mosquito in his bill.

The third and fourth photos are male and female examples of the Auckland Islands race marrineri on Enderby Island one of the Auckland Islands group. Both males are females are mainly black and white, the male being glossier with only a trace of yellow on the breast. The race is named after New Zealand biologist George Marriner who took part in the 1907 Sub-Antarctic Islands Scientific Expedition.

The Snares race dannefaerdi is the most distinctive, photos 5 and 6, with both sexes being completely black, the male again being glossier than the female. It is named after Sigvard Dannefaerd who was a Danish collector and photographer based in New Zealand and the original specimen was from his collection but ended up with the second Baron Rothschild who described it.

Back at the Birdway website, I’m continuing to redevelop it for mobile devices and the latest changes include the Bird of the Week page and I am gradually working my way through the various families in taxonomic sequence (that word again!): MegapodesChachalacas and GuansGuineafowlNew World Quails and, in progress, the Ducks, Geese and Swans.

Greetings

Ian
**************************************************
Ian Montgomery, Birdway Pty Ltd,
454 Forestry Road, Bluewater, Qld 4818
Tel 0411 602 737 ian@birdway.com.au
Bird Photos http://www.birdway.com.au/

Recorder Society http://www.nqrs.org.au


Lee’s Addition:

The little birds (sparrows) have places for themselves, where they may put their young, even your altars, O Lord of armies, my King and my God. (Psalms 84:3 BBE)

What cute little birds. I am glad the Lord saw fit to create birds in so many different sizes. Looks like Ian has been busy working on his website. I am sure he would appreciate you looking around again for his improvements.

Ian’s Bird of the Week

Ian’s Petroicidae Family

Petroicidae – Australasian Robins Family

Gideon

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