London Raptors: a review of September 2008

by

Des McKenzie


Source: BirdGuides


Verbatim Account:

September 2008 turned out to be a memorable month for raptor-watching across the London recording area

(and elsewhere), the most memorable since the jaw-dropping and unprecedented influx of Honey Buzzards back in

2000, when London amassed 161 records between 21st September and 14th October (Self: 2000).


Many of us back then considered the influx a spectacle we'd probably never witness again over these shores,

and indeed the sheer volume of birds involved may never be equalled. So it was with much anticipation that

birders scoured the skies over local patches from the 13th onwards once it had become clear that 'numbers'

of Honey Buzzards were clearing east-coast sites and beginning to head inland and south (along with enhanced

numbers of Ospreys and Common Buzzards). Many will have been hoping for a taste of what they'd had (or hadn't

had) eight years previously and, of course, duly went looking.


As it turned out, this year's influx wasn't as sustained as that in 2000, nor were there as many birds

involved; it was, however, a noteworthy event (and red-letter day) wherever it occurred, an event that

prompts that question 'why?' and 'when next?', neither of which I've attempted to address here.


A good proportion of the Honey Buzzard reports during September came equipped with time, flight-direction,

and colour-morph/age detail but unfortunately quite a few didn't, thereby making it that much harder to

determine how many birds may have been involved. However, by gleaning online information and detail

supplied to me privately I've been able to construct a reasonably accurate assessment of the influx.


The notes that follow summarise London-area reports for the above species during September 2008 with brief

reference to Red Kites, Marsh Harriers and unidentified medium-sized raptors (some of which are thought

likely to have been Honey Buzzards). Apologies for any errors or omissions.


It is unlikely that all the reports that made it onto the bird information services and/or online sightings

pages will end up being received as formal submissions by the relevant recorder; this would be a shame

though, as the more records submitted the better the odds on attaining as accurate as possible a summary

of the influx over London (and elsewhere of course). Conversely, it may be that additional reports are

received by recorders which are currently not in the 'public domain' so reference to the 2008 London Bird

Report should, in due course, provide a more definitive account for the species covered here.


Honey Buzzard


The first report of the month concerned a single south over Hornchurch at 10:04 on the 8th (this is still a

very scarce bird in the London Area, with just 33 records before the 2000 influx). This was followed, on the

10th, by a dark morph southwest over Wormwood Scrubs at 08:45 and one, possibly the same dark bird, southwest

over Richmond Park at 10:15.


The 13th saw the first real signs of a national influx, with at least 170 birds reported by dusk, mainly

from east-coast counties, the majority over Norfolk and Suffolk sites (but with a further four counties

reporting double figures). The largest numbers seen anywhere that day consisted of 18 birds drifting

south over Minsmere RSPB, Suffolk, over a 4-hour period. London, predictably, did less well but did

score a single bird, a (probably) dark-morph individual that moved high west over Rainham Marshes at 15:50.


Naturally enough, word spread fast among London's birding grapevine that an influx was underway and that

evening comments were exchanged on the London Birders Yahoo group predicting at least some reports from the

capital the following day. Fortunately it would be a Sunday, the weather looked promising, and the predictions

proved to be spot-on.


The 14th saw continual arrivals at east-coast sites and a conspicuous southward movement had became obvious.

Some 190 birds were logged before dusk (possible duplication from the previous day's birds aside) with

Norfolk in pole position in terms of the number of individuals reported.


The first strong wave of sightings now began to be reported across the London area with a highly respectable

ten sites (in five recording sectors) logging birds by the end of the day. Chronologically these were: west

over Hackney Marshes at 08:35; northeast over Rainham Marshes at 11:00hrs; southeast over Marble Hill

(Twickenham) at 13:45; northeast over Rainham Marshes at 14:00; north over Clissold Park (Stoke Newington)

at 14:50; south over Paddington Green and southwest Hook/Chessington at 15:20; southeast over Cheshunt at

15:55; SSW over Bedford's Park at 16:00 and southwest over Leyton at 16:14. There was also a bird reported

northeast over the London Wetland Centre but I've struggled to find any time or colour-morph information.

All reports referred to single birds with the exception of the Bedford's Park record, which involved two.

Of these, five were noted as dark-morph juveniles, two were intermediate types and one was pale; the

remainder didn't specify any plumage detail.


The 15th produced three reports of singles: an intermediate bird south over Waterworks NR at 10:25, and

birds south over Cheshunt at 11:15 and southwest over Alexandra Park at 18:30. No reports were received

on the 16th or 17th but a further three surfaced on the 18th, again all singles: juvenile over Isleworth

at 07:20; dark-morph juvenile south over Osterley Park at 10:00 and a bird west over Ewell at 14:05. On

the 19th clearly different birds went WSW over Banstead at 16:14 and Regent's Park at 16:35. No sightings

were reported on the 20th but on the 21st singles were noted from a further two sites: Pole Hill (Epping

Forest - with no further details) and a dark-morph juvenile south over Clissold Park (Stoke Newington) at

15:30.


Sightings over the next six days were non-existent then on the 28th a single bird was seen heading south-west

over Holmethorpe Sand-pits. The final sightings of the month came on the 29th, both singles: a dark-morph

juvenile north over Raynes Park (Merton) at 10:17 and another SSW over Beddington SF.


Common Buzzard


A sizeable 33 sites reported Common Buzzards during September, the vast majority being singles. Records

before the 14th, however, were sparse, though the 14th itself produced reports from at least ten sites,

most notably Beddington Sewage Farm where 13 passed over during the course of the day (there were also

eight over Amwell, four over the London Wetland Centre and four over Tyttenhanger). Other counts after

the 14th included six over the London Wetland Centre. Four were at Tyttenhanger on 15th, and four at

Fisher's Green (Holyfield Viewpoint) on 17th. The best count during the month from Trent Park (a site

that regularly reports Common Buzzards) was five on the 22nd.


Unidentified species


Ten sites reported unidentified, medium-sized raptors, all of which were 'buzzards' with the exception of a

probable Osprey over Paddington Green on the 14th. All of these birds occurred over the 14th and 15th,

thereby indicating a link with the 'Honey Buzzard influx' over London and nationally. On the 14th,

possible Honey Buzzards included two west over East Tilbury at 11:15 and two over Leyton later in the day.

A further possible, dark-morph, Honey Buzzard flew east over Alexandra Park at 17:52 on the 15th.


Other species


Marsh Harriers (apart from a regular juvenile at Rainham Marshes during the month) were also a feature of the

period, with single birds reported moving south over Amwell at 08:15 on the 13th; south of Northfleet at

17:30 on the 14th; an adult male west over the London Wetland Centre at 09:40 on the 15th and a

female/immature west over West Thurrock at 10:37 (also on 15th); a juvenile west over Queen Mother Reservoir

at 12:00 on the 23rd and northeast over Tottenham Marshes at 09:33 on the 25th. Red Kites were far less easy

to track down and the only reports, perhaps surprisingly, were singles west over the London Wetland Centre

at 10:55 on 14th and at Tyttenhanger on the 27th.


Summary


September 2008 produced a maximum of 28-29 (though this probably actually related to 20-23) Honey Buzzards

over a total of 24 widespread sites across the London recording area, most notably so on the 14th when

reports came in ten sites (maximum of 13 birds). A significant showing of Ospreys (17 sites) was also a

feature of the month (particularly on the 14th when a maximum of 8-9 were noted) while Common Buzzard

reports, although seeming to increase exponentially year on year in London, were well up on what would

normally be expected at this time of year.


Des McKenzie, Inner London Recorder

Saturday 11th October 2008



References/Sources of information

Self, A., 2000. Honey-buzzard Influx Autumn 2000. Lond. Bird Rep. 65: 191-198

BirdGuides Review of the Week and latest sightings pages: 11th-17th September 2008

LondonBirders Wiki Group; LondonBirders Yahoo Group; Dip or Glory website; East London Birders Forum website;

Surrey Bird Club website.


Comments by NR:


A much better researched and thoughtful article than those in Birding World or the Daily Telegraph. Some interesting points arise for further discussion:


  1. Since very large numbers of observers are on the east coast in September, it would be expected that most reports would come from this area if there were a movement down the eastern side of England. Observer bias needs to be considered.

  2. Twice in a Lifetime is a major theme!

  3. The decision not to comment on the 'why' and 'when next' is well-considered at this stage.

  4. The southwards movement of Honey Buzzard was well-established on the 13th as well as on the 14th: this direction was conspicuous from the start.

  5. The movement was not as prolonged as in 2000 because of the weather. In 2000 the winds were persistently from a southerly direction, blocking the birds' exit; in 2008 no blocking winds occurred for any length of time.

  6. Colour-morph information is interesting but not nearly as valuable as information on ages of the birds. Very few juveniles were reported on BirdGuides at the start of the movement, suggesting adults were involved, which are much more likely to know what they are doing migration-wise.

  7. The reported movement of Common Buzzard with Honey Buzzard is strange at first glance. The two species are not closely related, have different feeding strategies and the Common Buzzard has been thought of as highly sedentary in Britain. In Scandinavia Honey Buzzard move in September and Common Buzzard in October. Further, numbers moving through Falsterbo of Common Buzzard have been declining in recent years, not because of a population decline but because of more birds choosing to overwinter in Scandinavia. A Scandinavian origin therefore appears unlikely with the increase in migratory Common Buzzard apparently correlated with the recent increase in breeding Common Buzzard in eastern Britain. There may be an identification problem with some birds: recently fledged juvenile Honey Buzzard are very easily confused with Common Buzzard as they are extremely close to Common Buzzard in structure with shorter wings and tail than adults and juveniles that fledged some time ago. However, it does appear that the Common Buzzard is now a regular migrant on the east coast of England (N in spring, S in autumn) and the origin of this movement demands further study as it may help to explain the movements of other raptors. [Change to text in blue font, to consider movement of Common Buzzard as now a well-established feature in eastern England, prompted by email from Johnny Allan].

  8. Overall a useful contribution to the debate.


Nick Rossiter 2008-9

Honey Buzzard Home Page