Week ending March 30th   Leave a comment

I have been in Germany and then England some of this week where the spring is much further advanced than us. It’s always a bit like time travel to head south at this time of year. The difference in timing between us and 300 miles further south is about 2-3 weeks. It’s even greater in big cities like London, where the “urban heat effect” adds to the naturally warmer southern climate. Cities have so much concrete to absorb heat and smog to conserve it, as well as all the sources of warmth that lots of humans living together generate, that they have their own microclimate with temperatures being several degrees warmer than their rural surroundings. Some gardens in central London will already the leaves pretty much out in all the trees and will have young blackbirds out of the nest. In Germany there were lots of chiff-chaffs singing and more arriving every day. Chiff-chaffs are traditionally the earliest warbler to return to the north. Occasionally they even winter with us although I haven’t had one doing so around Crail for a few years now.

Although climate change has been discussed a lot this winter – mostly in the context of extreme rain events in England – every spring I am reminded of it by the timing of the leaves coming out on the trees, the beginning of the nesting season and the first arrival dates of each summer migrant. In my lifetime of observing, the earliest dates of all these events have shifted earlier by a couple of weeks on average. The “on average” is important because each year there is a lot of variation. Last spring was 3 weeks late and the one before 3 weeks earlier. A couple of cold springs and a cold winter and global warming recedes from people’s perception. But climate is all about long term averages, not specific events, and average temperatures have climbed steadily for the last century. It is important to remember that we are only arguing about whether we are to blame for rapid climate change, not that it is happening. In the context of Crail, our resident animals and plants have always had to put up with an uncertain start of spring – sometimes early, sometimes late – so they are perhaps already well prepared for a change. It may be harder for the migrants to adjust to the change though. A chiff-chaff coming to breed with us from wintering grounds south of the Sahara has little idea of whether the spring in Fife is early or late so there are opportunities for mismatches in timing. Summer migrants, as do most breeding birds, rely on seasonal peaks of insects and they time their breeding with them to produce the most young possible. If they arrive too late because of an early spring, they may end up with starving chicks, produced after the food peak.

Curlew - most will be off to breed soon if they haven't already gone

Curlew – most will be off to breed soon if they haven’t already gone

We always lose our wintering birds through April as the summer visitors arrive instead. Some of the Crail shorebirds have gone already. Redshanks, curlews and oystercatchers that breed locally in the west of Scotland will have gone already. Others that breed further north in Iceland or the Arctic may stay with us until mid-May. But it gets hard to say which ones are late residents and which ones are birds from further south on passage through Crail from about this time onwards. The great thing about shorebirds is that when they migrate they really migrate, covering several thousand kilometres in a flight. Stop-over birds in Crail, like sanderlings, knot and whimbrels that will soon appear in places like Roome Bay, may not have touched down since leaving somewhere like Senegal in West Africa.

I was down at Cambo on Saturday, peering through the murk that the easterlies brought in at the end of the week. The rookery down at the burn mouth is really busy with the early nesting rooks already in full swing. There were about 15 wigeon also down at the burn mouth. Wigeon are another species that will move north to breed soon – perhaps to Iceland, perhaps to Scandinavia. Out at sea there were relatively few red-throated divers. This winter I have not seen as many as usual. They have either been feeding far out or wintering somewhere else. But there has been a steady stream of them past Crail as usual as they migrate northwards too.

Red-throated diver

Red-throated diver

Posted March 30, 2014 by wildcrail in Sightings

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