Basin Notes - April 2007

Blooms keep their own pollen out

Anyone who has been out lately making the most of our recent beautiful, sunny and warm weather will not have failed to notice the abundance of yellow in our local countryside - lots of "yellow on the broom", seasonal daffodils and, or course, primroses.

The often overlooked primrose gets it name from its early appearance - the "prima rosa" or first rose - and I guess its resemblance to some later flowering garden roses. Primroses must be among the most familiar signs of spring but there is more their pale lemon flowers than initially meets the eye.

For a plant, the whole point of flowering is to spread its genes via the male pollen grains to the female parts of another plant, of the same species. But when each plant often produces more than one bloom, the risk of self-pollination is high. Primroses, therefore, get over this by a nifty arrangement of their male parts (the anthers) and female parts (the stigma and style). Look closely at the flowers of a number of different plants, next time you're out walking in the sun, and you should be able to distinguish two forms quite easily a "pin-eyed" primrose, with a long central stigma and pollen-producing anthers tucked away in the flowers' "throat" and a "thrum-eyed" form with exactly the opposite arrangement.

Multiple blooms produced by a single plant are all of the same form, which ensures that a visiting insect (like our "under threat" bumblebee will not easily transfer pollen grains to the female stigma of another flower on the same plant. When an insect moves to a plant whose flowers have the opposite arrangement, any pollen attached to its body will be in perfect alignment for fertilisation. This ends my lesson on the "birds and the bees".

Speaking of birds, the annual spring migration is well and truly under way here in Angus eg, Sandmartins back at the Bridge of Dun and outside the main viewing platform of the Wildlife Centre (up on Rossie Braes) plus singing chif-fchaffs in Rossie Woods.

However, for me, the true harbinger of this spring influx of "foreign visitors" is the perky little summer visitor, the Wheatear.

As I mentioned, a singing Chiffchaff or Blackcap doesn't definitely tell that winter is well and truly over and neither does the sight of a Sandwich Tern fishing in the South Esk or off Montrose beach.

That's because all three species mentioned have taken to residing here in the British Isles in small numbers during the winter months, staying behind or visiting from further north. As a result they are discredited as "real" harbingers of the warmer season (hopefully) ahead. The Wheatear, however, does not fit into this category at all, and certainly doesn't shrink from its responsibilities as a proper "summer visitor".

The plumage of the male bird in particular - a military grey back, a starch white rump, breast with a peach blush, black tail tip, mask and wings - is evident now, along our coastal, flat sheltered "grassy" areas and is particularly beautiful.

Every single Wheatear dutifully returns to Africa each autumn, so you can rest assured that any smartly coloured/plumaged arrival you might see around Montrose at the moment is the real thing, perhaps breathless from its long annual journey (these birds migrate some 10,500 kilometres from their wintering grounds south of the Sahara in West Africa to breed on our moors and mountains). Having taken no "short cuts", it's the genuine seasonal herald.