NATURE NOTES - Small but perfectly formed

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EVEN though beautiful things come in small packages it’s so easy to overlook ‘little things!

Watching the birds on the feeder this week my attention was brought to bear on what I thought was a leaf blowing around in a rather strange fashion – in fact it was a wren mooching about looking for food in and out of our dry stone wall.

One of our smallest birds (only beaten by the goldcrest and firecrest) wrens are tiny brown birds with dark barring on their wings, tails, and ventral surfaces.

They have a light stripe just above their eyes and their throats are lighter than the rest of their bodies. Juveniles are darker than adults and the sexes look the same.

They have a narrow bill and a short tail, which usually points upward. This small perky little bird is one of the most common birds in the UK. It may be small but it is extremely boisterous.

In fact, you hear wrens more often than you see them. They probably started out as woodland birds but now will make their nests anywhere where you find trees.

Literally millions nest in gardens, parks, woods and even on the coast in scrub areas in the sand dunes nowadays. They eat small animals, such as spiders and insects. But when these are not available they readily switch to seeds and berries.

Wrens have round, short wings with strong distal feathers. These features are adaptations to living in dense vegetation. Round, short wings require less effort and room to suddenly take off or stop and they are easier to maneuver within obstacles. Having heavier, stronger feathers at the ends of their wings protects them from breakage when they inevitably smack something in their crowded environment.

Wrens sexes can be distinguished during the breeding season by the presence of either a brood patch (female) or a cloacal protuberance (male). Age can be determined by the number of spots on their fourth primaries.

Being small as well as bringing many advantages also brings many threats! Domestic cats are major predators of all our garden birds and the wren is no exception and being a ‘slower’ flier somewhat easier to catch for the pesky cat.

Their nests (of which the male constructs several before the female chooses which one he should complete and she’ll use) are preyed on by many animals, including crows and jays and weasels.

Interestingly, crows and jays also destroy empty nests.

Wrens have a few adaptations to help counteract possible attacks by predators or nest parasites. Cryptic coloration makes them and their nests hard to find, and their habit of building several nests makes the real nest harder to locate.

They also avoid nesting near established nests.

Despite these counter measures, cuckoos in Germany heavily parasitize them – something that I’ve not heard occurring here in the UK – unless you know different that is!