Birds & Weather

There’s a book by this title, by Stephen Moss: Birds & Weather: A Birdwatcher’s Guide.

Sadly, it’s out of print and hard to get hold of, so I’ve never read it. I think there’s a copy somewhere in the county at an obscure library I ought to look up. I do often think it must have been written with me in mind; after all, I have a BSc in Meteorology, an MSc in Wildlife Management and Conservation. Ergo, my profession ought to be the interface between birds and weather. I suppose. In fact, if anybody from Hamlyn is reading consider this my open invitation to hire me to write ‘Birds & Weather 2’, or perhaps ‘Birds & Weather 2012’. Even if it’s just a matter of updating Stephen’s earlier edition, which I’ve no doubt is excellently written from the standard of his more recent, most enjoyable books.

Unfortunately, my meteorological skills aren’t quite what they were. I certainly hope I retain above average knowledge, and the ability to re-learn the principles and interpret data should I need to, but I guess what I’m saying is that I’m out of practice. By contrast, some birders exhibit astounding knowledge of what birds they expect to arrive with a particular set of weather conditions. Mostly down to long experience, I’m sure, but it comes with an understanding of how the weather works that is rare amongst non-weather-heads.

The pay-out from knowing what to look for and when to go can be spectacular. Though no judgement was involved on this occasion, I managed to time a visit to Norfolk in October 2010 with a light easterly wind, ushering new migrants in from the North Sea, whilst departing friends stocked up for the journey ahead and waited on the weather. These weren’t textbook fall conditions, but enough to keep me very, very happy indeed: seldom have I been anywhere so incredibly bird-rich, especially the stand of pines at Holkham dunes which crawled with birds, flitting and hiding and hopping around every tree and bush. Not so many mega-rarities (though as a new-ish birder I wasn’t complaining about my first pectoral sandpiper, yellow-browed warbler and Lapland buntings), but they’re hardly needed with thrushes, finches and goldcrests arriving in astounding numbers. Wave after wave of song thrushes passed through the area during the weekend. There’s also the matter, let’s be honest, of ‘pleasantness’. Not many people actively enjoy being soaked or frozen.

If you want to try your hand at forecasting that fall-out, spotting the right swell for a seawatch, or just planning what to pack, there are better ways to search for impending conditions than the simple 5-day forecasts offered by the BBC or the Met Office (don’t get me started on some of the small-time private forecasting companies). First on your list should be learning to interpret synoptic charts – something I can, I say humbly, still just about do. For example:

The continuous, thinner black contour lines are isobars, which link areas of constant surface pressure. You can almost read this like an Ordnance Survey map, imagining areas of high pressure as hilltops, and low pressure as dips, since just as a ball rolls downhill, air moves from areas of high pressure to low pressure. More commonly known as wind. The more tightly packed the isobars, the steeper the ‘slope’, the stronger the wind. The overall wind direction can be interpreted from isobars, too, and will give you a pretty good idea of likely weather conditions. Just remember that air flows clockwise around areas of high pressure, and anti-clockwise around areas of low pressure, ‘depressions’.

Superimposed on the isobars are weather fronts – warm fronts, marked by semicircles; cold fronts, marked by triangles; and occlusions (where a cold and warm front have caught up with each other and merged), marked by a combination of both. In Britain, warm fronts tend to usher in milder air, as the name suggests, accompanied by generally light rain or drizzle. Cold fronts are normally more active: stronger updrafts lead to shorter, heavier spells of rain or showers, often followed by more sharp showers in cold, clear conditions swept in by the front. An active cold front will often be accompanied by thunder and hail. The last frontal type you’ll find on a synoptic chart is a simple black ‘stick’, marking a trough: an organised line of convection which normally produces showery conditions. Finally, faint dotted black lines tell you the atmospheric “thickness”, most useful for predicting snow: see this article from Wired magazine, written by a knowledgeable Reading Meteorology 2002 classmate, for a better explanation than I’ve room for here.

If this whets your appetite for having a go at being the next Michael Fish, you can find more information on the comprehensive Swiss weather links site Westwind here, along with links to just about any other European weather data you could want from their homepage. The snow depth forecasts and lightning plots are particularly fun.

So, birders should spend all of their waking, non-birding hours poring over meteorological charts, only venturing outside when conditions are in the sweet spot? When you won’t get wet, but the shifting winds will deliver the mother lode of rare and migrant birds? I’m not so sure.

My good friend Richard Smedley aka ‘The Rice Birder’ was recently on the receiving end of a biblical-scale soaking in the Philippines (his home for the next three years), but was rewarded near the end of this soggy mountain hike by co-finding a yellow-browed warbler, one of only a handful ever found in the country. Not to mention the spectacular mountain tailorbird. In fact, it was this experience that led him to suggest weather as my latest subject for bird-tinged consideration. More modestly, I chanced on a walk at my patch late Friday, at the end of a mostly dull, drizzly day, and caught a golden half hour of sunlight before sunset – and a good display from three species of the local resident raptors, buzzards, kites and sparrowhawks, all lit nicely by the late afternoon sun.

Both of which tales bring me neatly to my top birds & weather recommendation. Yes, weather can be important – it can make the difference between a damp squib of a day, whether literally or figuratively, and a birding spectacle. But that doesn’t mean we should be slaves to the weather. On a bad day, birds don’t simply slip out of view into some mystical hidden dimension. They’re still there, waiting to be discovered: and the more we go out, rain, wind, snow, hail, sun or otherwise, the more of them we’ll see. Of course, on this point I’m a hypocrite. It’s much more pleasant to bird in clement conditions. But I have a sneaking suspicion that if I followed my own advice and took a chance on the weather more often, I’d have a lot more decent sightings to report to you lucky readers right here on this blog. I’ll see you in the rainstorm.

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