Saturday, 3 December 2011
Unfortunately I’ve been rather office bound the last wee while. It hasn’t been in vain though, I’ve knocked out another PhD thesis chapter, and completed the GIS (geographic information systems) analysis necessary for the next one. However summer has arrived, and earlier in the week it was just too nice a day to spend in front of the computer. A far more appealing option was to head to the Dunedin Botanic Gardens to get my bird geek on with a friend and colleague, also named Ed. Our target species: the humble dunnock (Prunella modularis).
Dunnocks (also known as hedge sparrows) are a fairly small, drab, and seemingly unremarkable little bird. So unremarkable, in fact, that despite their abundance in urban areas many people don’t realise their existence, failing to distinguish them from house sparrows (Passer domesticus). While there are differences between the two in plumage, song and behaviour, to the untrained observer the bill is the easiest distinguishing feature. House sparrows have a broad, finch-like beak, whereas dunnocks have a finer, more needle like bill. This is how I taught my young son to tell them apart.
Their inconspicuous appearance, however, belies a far more ‘colourful’ private life, with all the possible mating strategies being exhibited by dunnocks. Monogamy (mutually exclusive), polygyny (one male, two or more females), polyandry (one female, two or more males), and a generous dose of promiscuity can all be found in dunnocks. Ed’s PhD is on the evolutionary consequences of this, and examining which strategies, under which circumstances, are the most successful in rearing offspring and ensuring the continuation of the genetic line. Over the past few summers Ed has been catching adults, monitoring nests, and doing paternity tests on the chicks to build up a big picture of the dynamics of an urban dunnock population.
Hopefully the pictures will give you an insight into the more enjoyable side of being a bird biologist-getting out in the sunshine and getting our bird geek on. For me it was a welcome opportunity to get out of the office. Now back to that data analysis….
Ed removing an adult dunnock from the mist net.
Colour bands are a common tool in ornithology, enabling biologists to tell birds apart.
Chicks are regularly weighed and measured to check their progress
And nest cameras are used to see which adults are feeding the chicks, and how often.