Keeping Watch at Dusk
It is five o’clock on a February evening and I have taken up my post at the back window overlooking the terrace. The light is slipping away but there is still enough to make out the roosting pocket, a small thatched globe of sisal and hemp, tacked against one of the oak posts.
I am watching for wrens.
The temperature has barely risen above freezing and occasional snow flurries remind us that there could be weeks of cold yet to come. After five minutes a wren pops into the roosting pocket. There is no hesitancy; a sudden arrival and flight direct to the hole. Over the next five or ten minutes another four wrens appear. They have different strategies for their approach. The second two creep through the bushes at ground level, before flying up for a quick inspection and a hop inside. One, notable for its paler underbelly, works its way along the pergola and inspects round the outside of the pocket before settling in for the night.
I wonder what goes on inside. Do they jostle for position, beaks pushed upwards for air, feathers fluffed to capture the warmth; do they exchange news about a good cache of insects for tomorrow. They are usually silent on the approach although just occasionally there will be a soft churr of recognition.
Tonight I saw five wrens but in hard winters, communal roosts can hold tens of wrens. The need for survival overcomes this species’ normal solitary habit. I feel privileged to have provided this small space for them. The roosting pocket was discovered last spring by a male who made a nest of moss but it wasn’t used. The male wrens apparently build several nests and then the female chooses her preferred spot. Perhaps the memory of this opportunity was retained by the wrens when they searched for a warm shelter in these winter nights.
A few days later I am back at my post. A south easterly is tangling the dead grasses and snow is forecast. The first wren arrives at seven minutes past five. We both wait anxiously as the minutes tick by. After five minutes he is out again, taking a look round, then scuttles, mouse like, along the pergola to a new nest box and pops in for a quick look. Then he goes back to the roosting pocket and another look round before taking shelter inside. Is it fanciful to imagine he is, like me, concerned at the lack of company?
About a quarter past five and in quick succession, the other four wrens arrive at the roosting pocket and settle in.
Wrens are not the only birds gathering as dusk falls. Parties of rooks and jackdaws have been passing, flying into a nearby poplar wood to assemble. The winter roosting patterns of rooks have been well documented by Mark Cocker in his book Crow Country¹. Rooks have both traditional breeding sites (rookeries) and these long–established winter roosts.
Yesterday we spent a chilly and blustery evening in the Yare Valley, watching the roost that Mark has patiently observed over several years.
The river was high, a north wind rippling it against the bank, clumps of reeds dry whispering against the swell. Two barn owls flew across the neighbouring meadows, brushing the air with their wings like pale moths.
Across the river, the field was sown with black shapes as the rooks gathered. Snatches of their calls buffet across to us, deep throaty croaks and the lighter chacks of the jackdaws. Then streaming in the half-light, was a smoke of birds, coming in low, below horizon level, crossing the river and heading for the wooded roost. We estimated maybe 10,000 birds but this roost can hold up to 40,000.
As Mark points out, these roosts are different from the opportunistic huddles of wrens in harsh winters. They appear to serve many more social functions including protection from predators, pair formation and bonding, and information about sources of food.
We left the riverbank as dark enveloped the valley and discussed the reasons why birds might fly so far to join one of these roosts. The sugar beet factory poured steam clouds across the night sky and mute swans clustered on the river. We made for our own roost – in the pub.
¹Mark Cocker Crow Country 2008