Wednesday, 30 May 2012

Raptor inspired ramblings

Howdy folks,

The past few months I've been doing a bit of contract work for the New Zealand Department of Conservation in some of the lovely alpine tussock grassland of Central Otago. With the PhD thesis just a week or two from submission, it's been a very welcome opportunity to get out from behind the desk, and away from the pressure of formatting and editing. 

When I'm travelling, viewing raptors is a particular interest, largely due to the paucity of birds of prey in New Zealand, though also the splendour and majesty they encapsulate (see my earlier post, raptor rapture). We do have an absolute gem, however, in the New Zealand falcon (Falco novaeseelandiae), as well as the Australasian harrier (Circus approximans). Last year I spent much of the summer radio tracking New Zealand falcons around a wind development site and monitoring their breeding efforts, and just last week I was lucky enough to hear, and then see, a newly fledged NZ falcon while out working. It can't have been long out of the nest, as many of its feathers weren't fully unsheathed, and it was busy preening itself to help the process along. This is the best time of year for watching NZ falcons. The calls of the juveniles make them easy to locate, and the interactions between the adults and the juveniles are fascinating to watch. Most exhilarating are food passes, when the adults will drop food items for the youngsters to catch on the wing. 


New Zealand's raptor fauna wasn't always so depauperate though. Unfortunately New Zealand has the dubious record for having one of the highest extinction rates in the world. Since New Zealand was first settled by people around 800 years ago, 40% of the terrestrial and freshwater bird species have become extinct. Among these is the largest eagle ever known: Haast's eagle (Harpagornis moorei). Weighing up to 15kg, with a wingspan up to 2.6 metres, and claws the same size as a tiger's, Haast's eagle must also have been a majestic sight to behold. Unfortunately, competition with the newly arrived human settlers for the flightless, herbivorous birds on which Haast's eagle depended saw it decline, and disappear forever. 


The impacts of human settlement on New Zealand's avifauna doesn't end there though. Seventy percent of the (remaining) terrestrial and freshwater bird species in New Zealand are threatened with extinction. So should we be concerned? If you're reading a blog about birds I'm guessing you'll say yes. As do I. As I pointed out in my my last post (globe trotting birds), birds are a huge part of our cultural identity. Birds are charismatic, visual, and conspicuous representatives of biological and cultural diversity. They feature heavily in iconography and religion, myths and legends: Noah sent a dove from the ark; babies are delivered by storks; birds adorn our bank coins and notes, as well as countless national coats of arms. The examples are endless. While funding for conservation may be dropping in the priority list of governments in tough financial times, failure to invest in the survival of bird species is a fairly profound statement. What is it that we are losing through the ongoing decline and extinction of such prominent icons of our own culture?


So go out, get your bird geek on. And while you're out enjoying the experience, take a bit of time to ponder the place of birds in our own cultural identity. 




New Zealand falcon (Falco novaeseelandiae)

Wednesday, 4 April 2012

Globe trotting birds

Howdy folks,

Once again I find myself off jet-setting, this has been quite a big year for it. This time to England to attend the conference of the British Ornithologists' Union. I've been in the UK a few weeks now, having a long overdue catch up with some friends, and plugging away at the PhD thesis. A few milestones were met last week, I finished the first draft of my final data chapter, and the first publication to come out of my PhD "Arboreal arthropod sampling methods for urban trees" is now available online with the Journal of Insect Conservation. 

Naturally, it wasn't long after arriving in London before I was checking out the local avifauna. Given the paucity of bird habitat in highly developed areas, such as central London, features that may seem fairly 'rubbishy' habitat can play an important role in maintaining at least some biodiversity. Hence the vegetated railway-side vegetation provided a few opportunities for getting my bird geek on and spotting a few of the feathered locals (train-spotting?) on my way out of London. A few pigeons, some sparrows, chaffinches, blackbirds, starlings, thrushes, dunnocks... wait a minute... looks I'm not the only one who's been doing some jet-setting. In the past year I've been lucky enough to travel in both islands of New Zealand, Australia, southern Africa (SA and Namibia), and now England. In the towns and cities in all these areas, spanning three continents, there is a high degree of overlap in the bird communities. So what's the story?

This 'biotic homogenisation' is one of the byproducts of urban development. Worldwide, local species suffer from high rates of localised extinctions in urban areas, while concurrently cosmopolitan species, such as pigeons and sparrows move in. The precise details behind this shift remain unclear, as so many aspects of the environment are modified by urbanisation, at scales ranging from soil microbial activity right through to wholesale atmospheric and temperature changes. I'll save going into these in more detail for another post though. So should we be concerned about this biotic homogenisation? I argue yes, for several reasons, two of which I'll outline briefly.

First is species conservation. As the area of urbanisation spreads through urban sprawl, species of conservation concern are increasingly found in towns and cities. In such situations, there is the danger that what may have been a localised extinction could potentially become a total extinction. This is further exacerbated by the fact that urban centres tend to occur in biological hotspots, such as river mouths and estuaries (again, think London), largely due to historic trade reasons. 

Second is national identity. The avifauna of an area is one of its most visual and defining characteristics. Coincidently, I've just come from a lecture on the cultural value of Polish 'stork villages', where people travel from miles around to visit small villages, where the rooftop nesting storks can outnumber the human inhabitants. As a New Zealander travelling overseas, perhaps being known around the world colloquially as a 'kiwi' means this relationship between avifauna and national identity is particularly pertinent to me right now. 

So how do we go about reversing this biotic homogenisation? That's the six million dollar question. If anyone has a quick and easy solution, do let me know. In the meantime, I'll keep plugging away on my research on how urban tree-scaping may play a role. 


City birds... an urbanised ibis, a photograph instantly recognisable as Australian.


Friday, 2 March 2012

my humble homage...

Howdy folks,

Being in the final countdown to my PhD thesis hand in date the writing efforts have been ramping up in a fairly major way. I had a paper accepted for publication, and knocked off another chapter this week, so I think I'm winning though. Much as I'm enjoying the writing process (if not the pressure), I've been grateful for a few opportunities to get out of the office and away from the computer. I've been doing some part time contract work for the New Zealand Department of Conservation, and also spent a week in the beautiful Catlins region (South East coast), helping teach an undergraduate ecology field course. With rugged forested hills right down to the coastline with its rocky points and sandy beaches it's a beautiful place both to work and unwind. 

A big part of the New Zealand forest experience comes from one of our most inconspicuous little birds-the grey warbler (Gerygone igata), to which I would like to pay homage. Despite their small size, and inconspicuous behaviour and appearance, their call is one of the most endearing aspects of getting out in the hills. As they are found in forests throughout New Zealand, their call is synonymous with the New Zealand wilderness experience. Waking up in the bush just wouldn't be the same without it. 

Thankfully, grey warblers appear to be relatively resistant to urban development, despite the general trend for insectivorous birds to be fairly sensitive to such environmental change. As such it's not uncommon to hear them in town, and I frequently see (and even more often hear) a resident pair around my office, despite being beside one of the main traffic thoroughfares through town. And even better, there's another resident pair around my home, and they often give me a welcome, relaxing dose of the forest atmosphere while I perform my morning ritual of coffee while reading the news. 

Coincidently, while we're on the topic of urban bird communities, I tagged along with one of my academic supervisors, Yolanda van Heezik, for a New Zealand Radio discussion on urban ecology research, on the weekly 'our changing world' show. Click on the link below to listen to the podcast, and the multi media viewer to enjoy the trilling of the grey warbler. 


till next time, 


bird geek out. 


'our changing world' urban ecology discussion




video
Grey warbler in the hand, note the diagnostic red eye.