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Wednesday, 16 March 2011

Things that tell me spring has sprung

OK, not the most difficult thing to work out - after all, there are daffodils and crocuses everywhere - but it's still interesting to look a little more closely. For example, a couple of days ago among the daffodils (various cultivars of Narcissus sp.), was one flower that stood out...

Summer Snowflake Lucojum aestivum ssp pulchellum
These are taller and more robust than Snowdrops (Galanthus nivalis) and have the green spots you can see above. The native form (ssp aestivum) is found occasionally in damp places in Britain, particularly the south. They are separated from ssp aestivum by this having minute teeth along the stem-edges, at least near the base, while in ssp pulchellum (the cultivated variety) the stem edges are smooth. Here, no teeth = pulchellum. There's also the very rare (a few sites in Dorset and Somerset) Spring Snowflake L. vernum, and their flowering periods overlap, but L. vernum has only 3 stamens and a clearly bilobed spathe. As L. vernum usually has a solitary flower (sometimes 2) and L. aestivum usually has 3-7 (sometimes 1 or 2), I did have to check...

L. aestivum showing stamens - more than 3
Stem showing smooth edges
Another sign of spring is of course the presence of bumblebees - they can be found at almost any time of year, but their activity (along with that of some other charismatic insects such as bee-flies, the Bombyliidae) does herald warmer things to come. So, when something bumblebee-esque flew past, I wasn't too surprised, but it didn't look quite right. Having followed it to its destination, a clump of flowering Lungwort (Pulmonaria officinalis), I managed to get the following shot of it feeding:

Male Anthophora plumipes feeding on Lungwort
Unfortunately it wasn't keen on staying still to have its photo taken, so I couldn't get a shot of the tarsal bristles, but this does appear to be a Hairy-footed Flower Bee Anthophora plumipes, and a male going by its pale 'mask'. This is a species known to fly from around mid-March so this is not unusually early, but as far as I know L. aestivum has generally been considered to flower from April. As is often the case with such observations, it's anecdotal, but I have to wonder if this is just one of the many natural phenomena that indicate an earlier spring start linked to climate change and the higher average temperatures now clearly seen. Certainly, more thorough analysis of phenomenological data suggests spring starts maybe 3 weeks earlier than it did several decades ago. If I have a spare moment (maybe longer than a moment...) I may have to look at the data on NBN to see if the earliest records by year have changed for either of these species...

Further reading

For bees in the south of England:

Baldock, D.W. (2008). Bees of Surrey. Surrey Wildlife Trust, Woking.

Equally excellent, and by the same author/publisher is 2010's Wasps of Surrey.

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