Having to untangle and rescue a couple of adult gannets with Bex a couple of days ago gave me an ideal chance to have a close, a really close look at one of Britain’s most impressive of birds. Having 150 000 of them on Bass Rock only a few miles away is a real treat as we see lines of them passing the island every day but we don’t often get the chance to see them close up. But getting up close and personnel to these birds allowed me to see some of their adaptions to their way of life.
Firstly their plumage is mostly white, strikingly white when seen far out to sea catching the sunlight. A theory put forward but yet unproven is that this is so that when a gannet dives for fish it can be seen from far away by other gannets which can then home in quickly on a potential food supply. So if true the plumage colour has evolved to be of benefit not just to the individual but the colony as a whole. Gannets have a tremendous bill. If ever handling a gannet great care should be taken to immobilise the bill first as they can peck for your eyes. This bill is strongly built, fits tightly together and is pointed to offer little resistance when entering the water at up to 62 mph in a normal dive for fish. Hitting the water at that speed you can only imagine how unpleasant it would be if you had nostrils in the normal place on top of the bill so gannets have nostrils actually in the bill protecting them in a dive. And inside the bill are backward facing serrations that help to give a good grip to fish caught. Unfortunately it was these serrations that had helped the 2 gannets get tangled in the fishing line.
Gannets feet are wonderful. They are black with a green blue line up each toe. Originally it was thought that males and females had slightly different coloured lines on their feet but that has now been disproven. So why have lines ? We don’t know but gannets have a rich range of body language to communicate with neighbours and mates on the colony, and feet play a part in this so maybe having line on them just helps to draw attention to what the birds feet are doing? Bill also play a part so maybe that is also the reason for the black lines on and around the bill? A bit like eye liner and lip stick? Gannets have amazing eyes. They are positioned to give binocular vision which better helps them pin point the position of fish when diving. But this is not all. Their eyes can also make an optical adjustment in a split second for working in air to working in water while also blocking out the ultra violet reflection that distorts the view of a darting fish under the water. Though most of the gannet is white it has striking black wing tips to the wings. The suggestion that the black pigment strengthens feathers so this is concentrated in the places where the greatest wear and tear is found, at the ends of the wings.
And finally back to the most famous behaviour of the gannet, the dramatic dive. Though effective as way of catching fish it is hard on the bird. As a bit of protection the bird has evolved air sacks under the skin that offer cushioning against the impact of the water, a bit like bubble wrap.
But just in case you were thinking that gannets were perfect birds after handling the 2 birds for 30 mins I found out that this is not the case. Once back at the cottages I quickly found out that gannets are riddled with feather lice around the head and neck and I had an interesting 15 minutes trying to pick them off my hair and clothes. I still itch to think about it. And the seabird researchers made me pot all the lice so they could identify them!
If you want to see some gannets on the Bass Rock why not go to the Scottish Seabird Centre live streaming web cams?