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Déjà vu

posted 6 Aug 2014, 10:22 by Philip Collins   [ updated 6 Aug 2014, 15:38 ]

The end of the fieldwork season has snuck up on me once more; or rather it has abruptly smacked me in the face.

Unfortunately it’s not the end to fieldwork I had hoped for, as once again the kittiwakes have had a frankly abysmal breeding season. All birds in my study plots (consisting of ~40 active nests) have failed to successfully fledge young, and furthermore our control colony, which we monitor as an indicator of island productivity free from the influence of our work, has had a similar success rate.  Here only five chicks from 71 nests survived to the fledgling stage. This is less abysmal than last year’s grand total of 0 fledglings, but only slightly.

   

Kittiwake chick before it kicked the bucket, shuffled off its mortal coil, ran down the curtain and joined the bleedin' choir invisible…

Although we can’t be certain of the causes of breeding failure across the entire colony, we do know that a fair few of the chicks from my study nests (and therefore probably others on the island) were depredated by a Peregrine Falcon. As with last year we managed to capture this predation on some of the remote cameras stationed around the island.

 

Before and during images captured by the remote cameras of the peregrine eating a chick. Click to enlarge the images!

One cannot complain though as predation of this type is all part of the norm for these populations. In fact it’s pretty interesting to capture the peregrine repeatedly tapping in to this reliable, easy food source; I've started thinking kittiwake nests should instead be referred to as peregrine larders.

Despite this blog starting to read like the seabird equivalent of a Greek tragedy (albeit much less thrilling), all is not doom and gloom. My project was designed to address the overarching question of “Do phenotypic traits explain reproductive skew in kittiwakes” and as such a lack of reproductive success does throw a spanner in the works. I do however have a wealth of data including (and not limited to): high resolution accelerometry from numerous adults, morphometrics from yet more birds, and a seemingly endless number of images from the remote cameras I had stationed around the island. By seemingly endless I actually mean 314,897 images, which is close enough to endless for me (I am not a mathematician). This means that I have had to adjust the focus of my work and will use these data to answer other novel questions regarding the breeding biology of kittiwakes. As far as I am concerned this is all par for the course when it comes to  scientific research, in fact for me it is a large part of what makes it all so engaging. Inevitably studies such as mine should be dynamic and reflect what is happening in the real world including the difficulties faced. In fact if you showed me someone who says that their PhD had turned out exactly as they had initially planned, I would quite happily show you a liar.

Shifting away from my sob story and the implications of all of this for me, such periods of low reproductive success, although far from ideal, are not hugely uncommon or disastrous for most seabird species. Kittiwakes are long lived birds, meaning that they are likely to have numerous opportunities to breed throughout their lifespan; therefore these years should be viewed in a wider context. To effectively get a sense of context, long-term monitoring is required.  This is something that those of us working on Puffin Island are hoping to achieve through monitoring productivity repeatedly across years (we have five years of monitoring so far). We also feed our data in to the Seabird monitoring programme further allowing the data we record to be viewed not only over time, but also in relation to other colonies across the UK.

Productivity data from kittiwakes and shags over the last 5 years. 

So for me my fieldwork is over and I will now get cracking with the big write up.  No doubt I’ll be pining for Puffin Island again, especially when I'm locked up in a dark room sorting through the 314,897 images from the remote cameras.

 

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