Line transecting

After a bit of hand-wringing and a chat to Linda back in Aberdeen, we concluded that we wouldn't be getting much work done if we wait for the weather to be good enough to chase birds.

Although not as useful as following adults to their feeding areas, we could at least do some line transecting. This is a standardised survey where you pinpoint all birds you see as your boat follows fixed lines. This should really be done from a bigger boat, but we had already decided that it would be perfectly valid to do this from a smaller boat, because nearly all of the birds we would see would be flying (I won't go into the details of the methodological considerations here). We would take the range and bearing to each bird, so we could pinpoint more accurately where they were actually feeding.

The previous day, I had plotted out a random route worked out by Linda. As always, it's important to put these onto an Admiralty chart to ensure the route doesn't take us over any rocks or other obstructions.

Although the route was a bit bumpy in places during the day (Seastate 2 or marginally higher at times), and wet in the rain, we managed to complete seven transects. We found it a bit challenging at first - the first line had a lot of birds on it for the first 10 minutes - and we struggled to identify birds and write down all the details onto wet data sheets. But we coped. I am conscious that without a good way to estimate distance, that this method is dependent on us measuring distances to birds accurately, or at least consistently.

The comforting thing about the day was that we saw few birds over waters deeper than 40 metres, and the two northern-most transects we followed were almost completely devoid of birds, apart from a couple of individuals transiting at the coast.

All told, we felt we had done something useful, and have found something that will keep us occupied while we wait for the weather to go calm enough for us to follow individual birds. However, with the wind forecast to increase again over the weekend, we will have to wait until we can get out to sea.