The images from Alan Coles, below, capture a rufous morph Cuckoo in flight over Summer Leys LNR on 5th May. This is interesting on two counts – firstly, because this colour morph is generally uncommon, with only one or two reported in Northants per year and secondly, because records in recent years have come from Summer Leys/Earls Barton Gravel Pits (last year’s here) suggesting this may be the same returning individual.
Colour polymorphism in birds is determined genetically and the similarities between plumages of rufous females and Cuckoo fledglings (see here) suggest that the rufous morph is simply a colour alternative to the grey morph and might have arisen through paedomorphic retention of juvenile plumage to adulthood (see Trnka, Trnka & Grim).
Clive Bowley came across this super rufous morph (sometimes called ‘hepatic’) female Cuckoo near the feeding station at Summer Leys today.
One was also seen in the vicinity about two weeks ago. I’ve heard it said about 15% of female Cuckoos are rufous but I have no references on this and the proportion may well vary with geographical location. Rufous morph juveniles are much commoner, of course.
The decline of the Turtle Dove as a summer visitor to Britain has been well documented and it is believed to be at real risk of disappearing as a breeding species here within the decade. This is mirrored in Northamptonshire, where it has been recorded at only eight sites this year compared with thirty-six just ten years ago. Many of the records refer only to migrants and falling squarely into this category is this one at Stortons Gravel Pits yesterday morning.
Doug McFarlane managed to capture a few images before it was flushed by a dog-walker and not subsequently relocated. This individual is a smart adult. Let’s hope they don’t ‘turn turtle’ and disappear as a breeding bird altogether. For the latest news see www.operationturtledove.org
The last Cuckoo to be recorded in Northants in 2011 was on 26th August at Earls Barton GP – perhaps the individual below, which was photographed there on 14th August. Compare this rufous morph juvenile with yesterday’s grey morph at Crick. The white tips to the scapulars, wing coverts and tertials, along with the barred rump, rule out the rare ‘hepatic’ morph adult female.
This juvenile Cuckoo was present yesterday and again today at Foxholes Fisheries, near Crick, where it spent some time feeding from a fence post. It is a grey morph individual – many are also rufous, resembling the so called ‘hepatic’ form of adult females – and shows the white nape-spot characteristic of juveniles.
According to the BTO, Cuckoos have declined by 63% in England over the past 25 years and the now famous BTO satellite-tracking project has revealed that adult Cuckoos can leave the UK as early as the first week in June and be back in Africa by July. Juveniles are obviously later leaving but you won’t see many around from now on. There is a wide variation in the dates for recording the last ones in Northamptonshire, year on year. The latest record during the history of the Northamptonshire Bird Report (since 1969) was of a very late individual at Kettering on 17th October 1972 in contrast to the last one in 2010, at Earls Barton GP, on 4th July! There appear to be few local photos of Cuckoos and thanks are due to Joan Chaplin for supplying the images above.