Recent Sightings Friday 31st January – Excellent birding on a grey damp day - thanks to volunteer Phil for his report and photos.
The forecast grey and drizzly conditions duly arrived and stayed all day. It is easy to be put of birding in this weather, so I was pleased to see that we had more visitors than expected braving the conditions. I’ve long been of the view that birding can be rewarding in any weather and so it proved once again by some excellent views of some special birds.
Every autumn and winter the area around Pulborough Brooks attracts one or two hen harriers. This much persecuted and increasingly rare species seems to have a liking in winter for the flood plain habitat in this part of the Arun Valley, and the nearby fields up on the South Downs. On Fridays 24th and 31st a hen harrier spent the whole day hunting around Pulborough Brooks and could be seen at different times in most parts of the reserve. Hen harriers tend to eat small mammals but will also take birds, hence the name, and the contention with the grouse shooting industry in its moorland breeding home. In this photo from Nettley’s Hide it is in the centre banking to the right with many ducks in the air for safety.
The bird we’ve seen here is a “ringtail” which means that it either a juvenile bird or an adult female which look very alike. The name refers to the barring pattern on the tail which looks rather like segments of concentric rings when the tail feathers are splayed. The bird appears generally brown but lighter than the more commonly seen juvenile and female marsh harriers, is of a similar size and tends to drift quite low to the ground. However, it displays a prominent white rump so if this can be seen it is actually very easy to distinguish as shown in this photo from November 2017 taken from Winpenny Hide.
This prominent feature also aids identification when the light is poor as on 31st.
Several other birds of prey display the barring pattern on the tail, one of those being a barn owl. Recently one of these has been coming out to hunt about 1½ hours before sunset and has been seen on most parts of the reserve. Early morning visitors have also seen a barn owl hunting for a while after dawn. On 31st shortly after 3 pm I saw one in the field between West Mead and Redstart Corner. This field with its longer vegetation is ideal hunting territory for barn owls and a favourite spot.
This photo, showing the barring on the tail, was taken at Pulborough Brooks by Howard Kearley - he enjoyed significantly brighter weather than Phil did on Friday!
After the big flood just before Christmas and a subsequent lesser one in mid-January I had been wondering how the population of small mammals might have been affected and potential knock on effect on barn owls and other birds of prey which rely on them for food. It is hard to be sure about the long-term effects, but it does seem that our barn owls are managing to find food for the time being. Since Christmas a barn owl has been using West Mead hide as a feeding station, hence the currently rather messy floor. A number of owl pellets have been removed from the hide for analysis in the hope of discovering its recent diet.
Barn owls are easy to spot when present, but at the opposite end of the scale is the water rail which has a habit of being very secretive in amongst the waterside vegetation where its predominantly brown and grey colour does not stand out. Higher water levels and ice can help to flush it out into the open however, and one has been seen several times near Nettley’s Hide in recent weeks since the great pre-Christmas flood. On the day of the flood itself (20 December) I’d seen one briefly crossing the ditch in front of the hide, before the ditch was subsumed into the rapidly forming lake. On Friday it was feeding quite openly on the grass and mud just beyond the ditch, staying there for several minutes and using its relatively long bill to probe for invertebrates in the wet ground.
The water rail population in the UK is fairly stable, but with only about 1100 breeding territories in the UK they are very uncommon. However it is also known that some birds come across from Europe in the winter to take advantage of our milder weather so this is the best time to spot them.
There was one more bird of interest to end the day. Arriving at West Mead hide in mid-afternoon one of our regular visitors pointed out a black swan with a group of mute swans in the distance near the riverbank.
It seemed likely this was the same bird I’d seen at Amberley Wildbrooks on January 20th while undertaking the monthly Wetland Bird Survey.
Black swans originate in Australia and feature in many collections of wildfowl from where some have escaped. There is now a small feral breeding population in the UK so it’s not clear whether Friday’s bird was one of these or an escapee. It is not clear yet whether this population is self -sustaining or whether it relies on further escapees joining to boost the numbers and the gene pool. Either way it seems likely that black swans will eventually establish such a population and join the ranks of British birds in the same way as Egyptian Geese for example.