BOP Mystery

[bodshi]

Sorry to have to ask this because it's such a vague question, but it's driving me mad. Went for a walk yesterday evening with dog and OH, forgot binoculars but so rainy and miserable didn't think we'd see anything anyway. Of course, the rain immediately stopped and it turned into quite a pleasant evening.

In an area where I've seen mysterious BOP before - open flat farmland close to a wood with lots of hedges and trees between the fields - a medium-sized BOP flew out of a tree ahead of us. It was larger than a kestrel/female sparrowhawk but smaller than a buzzard. All I can say about the colouring is that it was brown - no dark or light patches on its wings, tail or back, didn't get a good look at the head, it had long wings and it just dropped from the tree and flew away from us just above the ground, mostly gliding but with a few flaps here and there. It flew on for ages, but keeping just above the ground and it looked as if it was just floating or drifting away. Wondered if it was a juvenile as it did let us get quite close up before it flew off.

Thing is, in the past couple of years, always at this time of year I've had a few sightings of a BOP similar size in the same area and the same kind of flight - dropping out of a tree and drifting away just above the ground or crop. Previous years the birds I've seen looked to have a grey back though. I've always seen them in the evening (and no they're not owls). Last year I also saw one flying extremely fast that startled me by crossing my path just a few yards ahead, flying at about waist height over some rough vegetation.

Anyone got any ideas? Would be most grateful for any help!

[Jenny W]

I was thinking perhaps Short Eared Owl until you said it wasn't an Owl. Are you sure it was smaller than a Buzzard or bigger than a female Sprawk, size can be hard to judge, especially at a distance (I know I'm rubbish at judging size!).

Depending on where you are could it also be a Hen Harrier?

[Rob_D]

Marsh Harrier?

[bodshi]

Thanks, have been busy searching Internet & now watched some youtube vids of harriers at your suggestion. Certainly seems to fit the bill as far as flight is concerned and I did see a female Marsh Harrier a couple of miles away last summer. We are about 12-15 miles from Blacktoft Sands as the crow flies and there is a lot of farmland south of us that's pretty inaccessible unless you happen to be the farmer, so don't know whether it hides any reed beds.

I know what you mean about judging size - this one was quite close so it was quite easy to see how big it was, but that doesn't particularly help as I usually see birds quite a distance away so not sure how big they are in comparison! It definitely wasn't a sparrowhawk (we have them in the garden) or buzzard (there is at least one locally that we love to see) - much longer wings I think in comparison to it's body.

Thanks for suggestions, harrier is looking likely and although it's difficult to get a sensible answer from the Internet it looks as though Marsh Harrier would be most likely round here - we are in lowland East Yorshire. We'll be going out again this evening, definitely with binoculars this time (which means we probably won't see a thing!)

[Picidae]

Habitat sounds good for Sparrowhawk, Buzzard, Kestrel or possibly Goshawk (provided the 'woods' you describe are fairly dense and mature).

I think you could probably rule out Hen Harrier, the white rump is very visible even on poor views, especially as you seem to have had several views of the upperparts of the bird in recent years. I doubt Marsh Harrier is likely on farmland/wooded areas and I don't associate these with perch hunting/dropping out of trees - they flush flocks of birds - waders/ducks - and this time of year, certainly the wrong habitat for breeding.

Kestrel, I'm sure you are familiar with and would have seen it hovering at least once or twice in your obs over the years.

Which leaves Sparrowhawk, Buzzard or Goshawk. With all three, size can be difficult to judge - a female Sparrowhawk could easily be confused with a male Goshawk and a female Goshawk easily confused with a male Buzzard!

As far as your description of hunting: Sparrowhawks tend to have a more active flight than you describe when hunting low - flapping their wings more and slightly undulating - a Goshawk has a much steadier stronger flight when pursuing flushed prey low to the ground and flaps its wings less - they make a fast contour hugging flight very low to the ground having dropped down from a tree perch - (as compared to other Gos hunting techniques such as foraging through dense woods or high soaring/gliding and stoops). Buzzards also hunt from tree perches low to the ground at times, however, again, the flight description doesn't quite fit: They have a much more active flight in this hunt mode, flapping their wings frequently and altogether look more 'untidy' and like Harriers/Barn Owls etc tend to quarter their hunting site looking for prey rather than pursuing it having spotted it from a perch - they tend to cover less ground in the amount of time it takes a Gos or Sparrowhawk to cover.

On plumage 'description' - This time of year, you're right, it could well be a juvenile bird which could explain the 'darker' appearance - you don't seem to have had decent views of it's underparts - am I right in thinking most views have been the upperparts each time? - As you probably know, Common Buzzards come in all colours - so a dark morph Buzzard can't be ruled out. Gos generally look grey or brown above, and if they are the same BoP you see each year, ie. 'grey' previously, that doesn't sound 'right for Buzzard but would fit Sparrowhawk or Gos. Gos also give the impression of being 'long winged' with their hands being more pointed than Buzzard.

Interestingly, you make no other mention of BoP in this area at other times of the year, suggesting a species which moves from it's breeding site to a winter site for food - this might be a slight point in favour of Goshawk.

Of course, none of the above are hard and fast rules but perhaps might ring some bells with what bird you are seeing each year - However, without a clearer description of plumage (ie. the underparts especially!) it would be hard to rule out Sparrowhawk, Buzzard or Goshawk.

I suggest you try and get out there with a camera - even a mobile phone image may help!

OOPS just realised what a loooong post that was - sorry! (Can't resist a challenge though )

[diggleken]

Near blacktoft?
Then quite likely to be marsh harrier from your brown type bird description or hen harrier gray in previous years you mention.
Marsh will 'roost' in trees for a bit of a rest then whizz towards the feeding site at the ouse marshes etc.
My bets on marsh harrier.
Cheers
Ken

[Picidae]

Originally Posted by bodshi

In an area where I've seen mysterious BOP before - open flat farmland close to a wood with lots of hedges and trees between the fields

Post two:

I did see a female Marsh Harrier a couple of miles away last summer. We are about 12-15 miles from Blacktoft Sands as the crow flies and there is a lot of farmland south of us that's pretty inaccessible unless you happen to be the farmer, so don't know whether it hides any reed beds.

If you'd mentioned this in your original post (rather than just the info in the first quote) which my reply was responding too, I certainly wouldn't have ruled out Marsh Harrier on habitat!! Plumage especially fits juvenile/or older female, and wing flight description would fit - they will hunt for food in over open marsh/farmland near to breeding location and will take advantage of summer prey of small mammals/will predate ground nesting birds/flocks of waders in fields etc.

Always good to mention your location and as much detail of surrounding areas as possible when looking for an ID

[FUDGEY]

I'd go for Goshawk as you mentioned it was flying v fast on one occassion, never seen a marsh harrier, but plenty of hen harriers and I assume they fly at pretty much the same rate which I wouldn't describe as fast.

[Dogghound]

Marsh harriers are quite wide ranging we have had a couple up here in recent weeks not particularly near any breeding habitat. Had a female today on the coast.

[bodshi]

Thanks for replies, yes could have been more descriptive with the location but didn't want to bore anyone! Will bear in mind for future though.

The nearby wood is very dense and mature, it is very private with secure barbed wire fence - reason being there is a pheasant hatchery in there somewhere - but will only be about 10 acres, not sure whether this would support Goshawk, but it seems to be where the buzzard/s have made their base (first buzzards we've seen round here - 3 last year but only one recently)

You're right, I've only really ever seen the back view of these birds as they fly away from me. The thing that is so similar is the way they drop straight down from the perch and fly so low, seeming almost to float but in reality travelling at a surprising speed. The very fast flying one I saw I can only describe as being like a jet aircraft! It was so fast and as it went past it just slightly tipped a wing and changed direction, without beating a wing. It was an experience that just left me standing rather foolishly with an open mouth thinking "what the heck was that??!!!". Of course that might have been a different species from the 'floaty' ones - that one definitely had a grey back and I could easily have thought it was a sparrowhawk except that it was far too large - as I say we have visiting sprawks in the garden so I know how small they are.

I was thinking - I know it's always this time of year I see these mystery birds because it's when they're harvesting the fields - so maybe I'm on the wrong track and it's not so much the season as the fact that they are harvesting - especially if they come to hunt the small mammals that must be disturbed by the harvest.

Thanks for help. Wish I could have got a better view of the thing! Went out to look again yesterday and saw ... absolutely nothing!