Category: Raptors

This spring the BTO is organising a nationwide Peregrine survey to record the number of occupied territories in the UK, Isle of Man and the Channel Islands. Details are on the BTO website here and they will be working closely with established groups that study raptors to complete a comprehensive survey of all known territories. Another aspect of the survey is checking for possible breeding in randomly selected 5×5 km squares and there are 14 of these squares in Northants (below).

So far volunteers are lined up to cover 10 of these squares – the remaining vacant squares are in the centre of the county:

SP77_SW	Cottesbrooke, Creaton, Brixworth
SP66_NE	East Haddon, Holdenby, Gt Brington
SP86_NE	Wellingborough
SP86_SW	East Edge of Northampton, Ecton

The aim will be to search each square for suitable habitat (e.g. quarries, pylons, industrial buildings, church towers) and to look for the presence of Peregrines. Apparently in some regions Peregrines will also nest in trees. Three visits to the square are recommended between March and mid-July. The first and second visits will be used to establish the presence or otherwise of Peregrines and the third visit to look for evidence of breeding success or as a further check for Peregrine presence in squares in which Peregrine detection may be particularly challenging.

Volunteers are required for the four remaining squares. If you would like to help, then please contact Barrie Galpin, BTO Regional Representative for Northants, 15 Top Lodge, Fineshade, Corby NN17 3BB barrie.galpin@zen.co.uk

While some of us were sweltering under canvas at Birdfair others were out in the field, finding good birds. Harrington Airfield was clearly the place to be as, at 08.30, Neil Underwood had a Marsh Harrier between the concrete track and the conifer belt. We’ve now had several in the County this autumn and no doubt there will be more to come. Later in the day, at around 17.15, however, Jonathan Philpot was lucky enough to discover a ‘ringtail’ Hen Harrier hunting over the fields between the concrete track and the first bunker.

Despite the rather pale underparts, lacking ochre tones, and the reasonably well-marked secondaries, I’m guessing it is probably a juvenile as its primaries are not strongly barred and, from above the secondaries are solidly dark, the primaries are paler but unbarred and there are pale fringes to the primary and secondary coverts.

Whatever its age, it’s a nice bird!

The continued presence of a Marsh Harrier at Pitsford Reservoir over the past few days has provided a good excuse for a snapshot of the status of this species in Northamptonshire. Seen only briefly in Walgrave Bay by Neil & Eleanor McMahon and Neil Hasdell on the morning of Saturday 28th, I caught up with it in the same spot equally briefly the following morning and, after being on view for only a couple of minutes, it promptly disappeared for the remainder of the day. Fortunately (for the yearlisters!) it was relocated the following morning when it was seen in, and between, both Scaldwell and Walgrave Bays around midday. It remains in the area this evening. 

Marsh Harrier is an uncommon, though regular, local passage migrant. Considering it breeds in some numbers in neighbouring Cambridgeshire shouldn’t we expect to see it more frequently in Northants? Especially in the east? Over the ten years 2000-2009 there was an average of 14 records per year, with a record 35 in 2010. The best time to catch up with one is in April-May or in August-September, although birds in spring tend not to linger. The best place is the Nene valley but the reservoirs have produced numerous records in autumn and, in theory, one could turn up almost anywhere. One wintered in the Nene valley between December 2001 and April 2002, being seen predominantly at Stanwick Gravel Pits. And the highest number together? Three juveniles at Pitsford Reservoir on 25th August 2002.

There are few photos of Marsh Harriers in Northants so Neil Hasdell did well to get the long-distance shots of the Pitsford bird shown here. This individual is a typical juvenile, aged by the plain upper wing coverts with fresh, pale tips to the greater and primary coverts and all flight feathers, forming a neat, narrow band across the upperwing and a thin, pale trailing edge. Additionally there is a pale crescentic base to the primaries on the underwing, barely visible in the photographs. Some juveniles also show an extensive creamy area on the upper forewing like adult females, while others lack the pale tips to the coverts and flight feathers altogether and so appear virtually identical to adult females.

If this isn’t confusing enough, and to make matters worse, adult males can appear identical to adult females as revealed by Sternalski, Mougeot & Bretagnolle last year in recent studies on populations in south-west France, where 40% of adult males exhibited plumage identical to adult females. In further analysis, Bavoux, Burneleau and Bretagnolle found the only sure way of sexing these individuals is by weight (females weighing more than males) and bill length. Assuming equal numbers of each sex in the population, then, 70% of all adults will therefore exhibit adult female plumage and, when you throw the immatures into the mix, this explains why the overwhelming majority of Marsh Harriers we see are simply chocolate-brown, cream-crowned birds! Bottom line: with many individuals you cannot be certain you are watching an adult male, an adult female or a dark juvenile of either sex!

In recent years Peregrines have habitually used the 418-foot National Lift Tower (formerly Express Lifts Tower) in Northampton to roost and to hunt from. Some 4-5 years ago a pair – which included an immature female – took up almost permanent residence and it seemed likely they would ultimately breed. However, around two years ago there was considerable prolonged disturbance at the top (the tower is now used for abseiling) and these birds now visit the tower only intermittently and they have been seen there far less frequently in the recent past. 

Earlier this month, John Boland visited the tower and found evidence of its recent use by Peregrines, as his photos below quite clearly show. All these carcasses are recent as the microwave antenna they use as a feeding platform gets cleaned on a regular basis.

Peregrine prey items (John Boland)

Visibly identifiable remains include a duck and Green Woodpecker but the identification of the remains of the other bird which, John says, is not quite pigeon-sized and is brown with a light-coloured bill, is unresolved. It is assumed that the good collection of small pebbles have come from the birds’ crops.

The view from the top of the tower is quite impressive, with the Stortons Gravel Pits complex clearly visible in the foreground.

 All photos: John Boland

It’s about time we had one this year and John Peacock was lucky enough to catch this individual as it passed over the footpath near the Screen Hide at Summer Leys this morning. Initially mobbed by a crow, it circled and quickly gained height before moving off north-west at about 08.15.

Plumage characteristics, such as the slightly darker secondaries than primaries, with barring conspicuous and filling the space between the covert barring and the darker trailing edge – as well as the outer primary barring extending out toward the darker tips – point to this individual being an adult female. Honey Buzzard is a scarce annual passage migrant with, over the last ten years, 2-4 records per year. In 2000 a record 37 were recorded as part of a national autumn invasion but prior to that there had been only 12 records in the 20th century.

While working in Rutland on Thursday, 12th May, Tom Lowe ‘videoscoped’ this Black Kite after it had drifted over him, high SSE, and crossed the River Welland into Northamptonshire between Collyweston and Easton-on-the-Hill. His videograb composite, below, leaves no doubts on the ID with perfect structure and the 6-fingered primaries

visible in the the top right and bottom left photos. This will be only the third record of Black Kite for Northants, the previous two were of singles near Long Buckby on 2nd May 1995 and at Summer Leys LNR on 7th May 2007, so May appears to be ‘the’ month. There have been a handful of previous reports but these have either been unaccepted or have related to escapes. Well done, Tom!