PBC: Marsh Harrier

Peterborough Bird Club annual report
Marsh Harrier Circus aeroginosus | A | Scarce

1998 | 1999 | 2000 | 2001 | 2002 | 2003

2003

Scarce migrant breeder and passage migrant.
The first bird of the year was a female at the Nene Washes on 6 Feb (RSPB) with a male there on 20 Feb (MM, OM) with numbers increasing to three by 26 Mar (SPD). The main arrival on the Washes was from 4 Apr onwards, with up to four birds seen there during the breeding season. Elsewhere, birds were recorded from 15 locations across the PBC area.
Numbers at the traditional Eldernell roost began to increase in mid-August, reaching a peak on 20 Sep with 20+ birds arriving to roost (MW). In past years, all birds had left by the end of October; however, in 2003, 2-3 birds were present until at least 22 Dec (RSPB) and a female was seen on the last day of the year (BHS). This is the first record of this species wintering on the Nene Washes.

Summary of counts at Eldernell Marsh Harrier roost 2003

August			September
19th	22nd	26th	1st	6th	7th	10th	15th	20th
10	6	13+	11	16	19	12	15+	20+

Breeding occurred on the Nene Washes where 4-5 pairs bred (RSPB). Success was not closely monitored but two nests fledged at least three young each. Breeding also suspected at Woodwalton Fen NNR.

2002

Scarce migrant breeder and passage migrant.
Once again, this proved to be a popular and well-recorded species. A very early male that turned up at Eldernell on 16 Jan (GRH) easily beat the previous earliest record, 20 Feb 2000. There were then further sightings of what was presumably the same bird on 2 Feb (MHo) and 3 Feb (MB), and the first female appeared on 17 Feb (BM). Birds were seen regularly in the usual Nene Washes general area regularly from then on. The main arrival was between Mar 27 and Apr 4, when up to eight could be seen at once (RSPB). Marsh Harriers wandering away from the Nene Washes district were seen at a further 12 locations.
The Eldernell autumn roost reached 20 birds by late August and numbered 18 on 5 Sep; the last bird was a juvenile seen on 30 Oct (RSPB). Another roost was watched at Baston Fen NR, with a peak of six in early September (per DV), and the last bird was seen there on 12 Oct (AD).
Six pairs bred along the Nene Washes; fledging success was not monitored closely, though one pair fledged four young and a second fledged at least three. In other locations, breeding occurred at Woodwalton Fen NNR and an additional undisclosed site in the PBC area.

2001

Scarce migrant breeder and passage migrant.
As with most birds of prey, this is a popular and well–reported species. The first bird of spring was a female at Dog-in-a-Doublet 8 Mar (BHS), with sightings from the Nene Washes RSPB reserve on the 9th and 13th with two there on the 28th (RSPB). From then on, 1–2 birds regularly reported along the Nene Washes until three (including a male) at Eldernell 22 Apr (MF). Wandering birds from the washes or migrants were seen at King’s Dyke NR on 15 Apr (GHR), Conington on 1 & 2 May (RD) and at King’s Dyke NR (male carrying a Moorhen chick) 15 May (GW).
The breeding population on the Nene Washes was slightly down on 2000, with seven pairs, of which five pairs fledged 16 young (19 young fledged in 2000), with the other two nests believed to have failed (RSPB). Another pair was reported by a farmer in another fenland location.
On 27 Jul, a second calendar-year male was found with a broken wing at Woodwalton Fen NNR and taken to the Raptor Foundation for treatment (RES). Away from the washes, up to five birds regularly seen at Prior’s Fen GP Aug–Sep (GW, SPD, BHS, GM, BM), 1–2 at Welland Bank GP and Deeping High Bank Aug–Sept (WB, AD, SPD, TW), singles at Stowgate 25 Jul (WB), Ferry Meadows CP 12 Aug (MJW), Orton Brimbles 22 Aug (MJW), Borough Fen 5 Sep (DB), Baston Fen NR 28 Sep (AD) and 17 Oct (JR) and Woodwalton Fen NNR 11 Nov (RMP, KW).
The autumn post-breeding roost on the Nene Washes reached 15 on 10 Aug, with at least 25 there 23 Sep (RSPB), after which numbers quickly dropped with only four birds on 2 Oct, three on 18 Oct and a single to 20 Nov (SPD, BHS).

2000

Scarce breeder and migrant.
The year's first record was at the Nene Washes of two females on 20 Feb. Elsewhere, a single was at Flag Fen on 3 Mar. By the end of March, three males and three females were at the Nene Washes. Spring sightings away from this area included 1-2 birds at Deeping High Bank 5 Apr, 7 Apr, 26 Apr, 1 May and 25 May, and similarly at Baston Fen NR on 7 Apr, 24 Apr and 31 May. There were four at Thorney Toll on 18 Apr and singles at Tongue End 7 Apr, Langtoft Fen 19 Apr, Ferry Meadows CP 5 May, Crowland 13 May and Morborne Hill 13 May.
During the breeding season, the population at the washes increased to nine females and eight males, with a minimum of 19 fledged young. The first young were seen out of the nest on 5 Jul. In autumn, there was a build-up to 20 birds at the Nene Washes on 7 Sep, with 1-3 in October.
Elsewhere, in July, singles at Baston Fen NR 1 Jul, King's Dyke NR 19 Jul and Crowland on 30 Jul, then 1-2 at Baston Fen NR 13 Aug, 24 Aug, 3 Sep, 17 Sep and Deeping High Bank on 3 Sep, 16 Sep and 28-30 Sep. Three were noted at Thorney Toll on 10 Aug and Prior's Fen GP on 23 Aug. Singles also at Baston & Langtoft GP 2 Sep, Drysides GP 3 Sep and Holme Fen NNR 17 Sep. A single remained at the washes throughout November and December.

1999

Scarce breeder and migrant.
The first of the year was at Orton BP 11 Mar (GW). This was shortly followed by the first on the Nene Washes 17 Mar. By mid-April, the Nene Washes held four pairs (two on the RSPB reserve, two at Eldernell Pit). However, the Eldernell reedbed was clearly too small for both pairs and one left. A male was at Cowbit 27 Apr (RD).
In May, sightings increased, with singles at Woodwalton Fen NNR, Ferry Meadows CP, Orton BP, Crowtree (Farcet Fen) and Baston Fen. The three pairs at the Nene Washes settled in and by mid-June were bringing in food. In July, a female was at Crowtree (Farcet Fen) 31 Jul (AL). The first fledged young were seen at the Nene Washes 9 Aug with the two nests in the reserve reedfen fledging seven young. No young were seen at the third site.
The autumn roost on the washes held good numbers and started to increase in August, with 14 noted.
During September numbers rose to 21 on 20th, though a range of 15-28 was estimated on 4 Sep (GRH). Numbers decreased at the end of the month, with six on 26th. Sightings at Crowtree involved a female on 11 Aug (AL), male and female roosting in a beet field 3 Sep and 26 Sep (AL). Elsewhere, one was at Orton BP 1 Sep (DP) and two were at Baston Fen 11 Sep (MH).
In October, two were on the washes until 7 Oct with a single juvenile thereafter. Singles were also seen at Baston Fen 3 Oct (EJR) and Farcet Fen 11 Oct (AL). November produced a single at Dogsthorpe Tip 11 Nov (per BHS), with the final sighting of the year coming from the Nene Washes, when the long-staying juvenile was last seen 24 Nov.

1998

Rare summer visitor and migrant.
Females were at Crowland Crossroads on 30 Apr (TW), Deeping High Bank (8 May) and Baston Fen on 9 May (AFB), Newborough on 15 Jun (TW), Guyhirn on 7 May and 16 Jul (TW), Baston & Langtoft GP on 6th and 16 Aug (AFB) and Helpston on 11 Aug (RA).
Males were seen at Ring's End on 17 Jul and 10 Aug (TW), Langtoft Fen on 31 Aug (TW) and at Thorney on 8 Oct (TW). A pair displayed on Baston Fen NR on 6 May (JW). Juveniles were seen at Deeping High Bank on 16 Aug (AFB) and Baston Fen NR on 25 Sep (TW).
Nene Washes: Passage birds on 16th and 19 Mar were followed by a male displaying and carrying nest material into the reedfen on 7 Apr. This attempt was thwarted by the flood but he soon attracted a mate to Eldernell Pit, where a nesting attempt was successful in fledging two young. Additional birds were present in May and June and several passed through. A pair also bred in the Counter Drain at Ring's End, though the outcome was unknown.
The autumn roost was not well-watched and peaked at only seven birds through August, six in September and two in October, with the last bird noted on 16th.