February 24th   Leave a comment

It has been unseasonably warm this week with afternoon temperatures reaching 14 degrees. Today we even had the haar rolling in: we usually only get this starting in April. The fog is formed on a warm day when the air heats up and then hits the cold North Sea. As it also gets warmer inland, the consequent inshore breeze then pushes the fog into Crail. It never penetrates very far because as the haar comes inland it warms up again. But Crail’s position with sea pretty much all around means it can sit on us all day. It can be very frustrating when the rest of Fife is having a beautiful day and we are shivering in the fog. When I arrived at Balcomie this morning the haar was still out towards Kingsbarns and it was beautifully sunny with a flat calm sea. I was able to check the dunlins and sanderlings flocks on the beach and the sea ducks offshore – still mergansers and common scoters but no long-tailed ducks. But then the beach and the birds started disappearing. It was enough to send me back home after half an hour imagining that the sea really was still somewhere out there in the grey at Fife Ness. A hundred meters inland the sun was shining again.

Sanderling

If you have been driving to St Andrews from Crail past Cambo this week you will have noticed the grey herons standing in the wheat field on the west of the road. On the east side is the heronry, in the tops of the few pines in the line of trees beside the road. Some herons are still adding sticks to their already large nests – repairing the damage caused by winter storms or just generally making them bigger. Grey heron nests aren’t as bad as stork nests that get bigger and bigger as they are added to every year, but some certainly look like they have been used for several years. Some of the herons may even be on eggs by now, although this would be unusually early for Crail. But everything has started much earlier this year: great and blue tits are nest building a month early and I bet there is a blackbird somewhere in a Crail garden on a full clutch of eggs already.

Grey heron nest building

It’s a risky strategy nesting early because the weather may turn colder, but the rewards are high with time for a second or even third brood over the summer. It’s less of a risk for very large birds like herons because the eggs take a long time to hatch anyway (a month versus 2 weeks for a blackbird) and the adults can protect them nicely against the cold when incubating. It’s the chick stage where the cold really makes a difference. The parents need to leave the nest to get food for the chicks and small chicks cool rapidly, not being able to thermoregulate until a few days old. A prolonged cold or rainy early chick stage can be disaster. A small bird will renest, of course, but each nesting attempt is costly, and any bird that gets the timing just right will be ahead for the year. So, an early spring is a tricky hope for the best for the resident birds. For the migrant birds, like the whitethroats or sedge warblers dues in two months’ time, whose time of arrival here is set by conditions much further south, and who can have no current local knowledge of breeding conditions until they get here, it is even trickier. Resident birds might start too early and then try again, but migrants can miss the boat entirely, arriving too late to time their chicks to the best conditions. This is one of the reasons we worry about climate change. It is unpredictability makes life difficult for animals: not warmer temperatures and rising sea levels (although they are a problem), and climate change is mostly about things becoming unpredictable or unreliable. But before I get too gloomy – we have had always had early and late springs, and the first egg date of something like a great tit can vary by over a month in two consecutive years for the same individual. Evolution has already put a lot of necessary flexibility in place – we will just have to hope there is enough.

Posted February 24, 2019 by wildcrail in Sightings

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