The Lincolnshire Bird Club

Hi,

Just as the light was beginning to fade in to half-light, wrens started to appear. First singles that would bob about in the cherry tree before entering the hole in the bird box in that tree, then small flocks each landing a short distance from the box before making their way inside for the night.
In the period of half an hour before dark, 30 wrens had made their way into the nestbox, safe and warm, snuggled together until daybreak.

What fascinating behaviour from possibly britains commonest bird.

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George Rutter

George,
This is not an uncommon phenomena but 30 birds seems exceptional - obviously a survival strategy during the current cold weather - I sincerely hope they all survive.

I remember in a 2 week severe cold snap in 1983? a nest box with 45 dead wrens all frozen together
and although wrens are Britains most widespread bird i think Chaffinch is the most numerous unless
thats changed in the past 5 years.
The cold weather has certainly bought some good numbers and species to my garden feeders so todays
RSPB garden bird watch will prove interesting.
regards John.

Hi John, George is correct, the wren at 8.6 million pairs is the UK's most common bird. Next most common is robin at 6.7 million then chaffinch at 6.2 million. Thats per the The state of UK birds 2012.

Hi George,
Well done for your observations.
It just goes to show that even common birds are exceptionally interesting. I will keep my eyes open in future for the sighting you witnessed.

Thanks for that set of stats Phil, i am obviously well out of date,and George is up to date, will be interesting to see
what the population of breeding wrens is this year ? .
regards John.

Update

Tonight wren numbers had dropped to just 11.

So does this show that this behaviour is brought about by temperature? as opposed to just time of year(winter) or general conditions or even habit? The big change since the last count is the night/day temp have increased a few degrees, however it is now windy and still raw but warm enough for the snow to have melted.

Not scientific i know, but it does get you thinking.



Cheers.

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George Rutter

as i understand George its a way of conserving body heat in very low temperatures, i have read of large groups roosting in nestboxes in previous severe winters and recall an observation of a roost of over 70 together in a large nest box.
regards John

I remember a few years ago with snow on the ground seeing a ball of about 20 wrens at dusk on the end of a branch all huddled tight together.

Update

The same nestbox has successfully been used to rear a family of Tree Sparrows so far this season.

Thats what you call a very useful nestbox.

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George Rutter