Furthest distance birds that can be identified? (1 Viewer)

[dantheman]

Just wondering this, as on a thread in the optics section someone is claiming they can make out skiers at 20 miles (aka black dots) with their new scope. Doing garden listing this year, and having a rubbish garden, most birds I'm getting are on courtesy of the optics, with some nice habo about 1200m away, and requiring a fair bit of perseverance and squinting.

Anyway, furthest I have got is Herring Gulls (wing and tail colour clearly noted on alighting) on tv ariels in Carnon Downs, 4.3 miles away (still id-able at rest, although not that much fine detail!). This with 27x eyepiece (Nikon ed50) and through double glazing. OS map used for distance verification.

Thinking at this rate something like Griffon Vulture in suitable conditions must be possible at over 10 miles. Size and distinctiveness obviously important. Anyone ever tried measuring??



(nb birds in flight, especially flocks, should be identifiable at longer ranges than when perched due to distintive flight modes, movement, and contrast to background, but then of course accurately calculating distance becomes a bit more awkward ...)

 

[Simon Wates]

On raptor migration surveys here in southwest Portugal, with radar assistance that provides accurate distance measurements, we have been able to positively identify Griffons at close to 8kms. However, as the temperatures are usually warm with some heat-haze and dust in the atmosphere it makes the long range images in the scope rather more tricky!

 

[Larry Sweetland]

I think that with a top scope, one of the smallest identifiable species must surely be my avatar, potentially identifiable in flight from a different island??

 

[Chlidonias]

I can see your avatar from here Larry, and I'm on the other side of the world! How's that for identification at a distance?

 

[Reuven_M]

How far away can you see a large flamingo colony?

 

[Bird_Bill]

Picked up 3 trumpeter swans over 2 miles out with naked eye yesterday at just before sundown.Not uncommon to use 7x - 26mm bins to do same at about 4 miles.Same for being able to discern mature vs. juv. bald eagle.Atmospheric conditions play a large part.This morning with visabilty limited to 600 meters because of fog,pocket sized doppler set be very handy.

 

[John Cantelo]

I think the problem is often one of getting an accurate 'fix' on exactly how distant birds really are from the observer - particularly, as will often be the case, with flying birds. The accurate ID of birds also depends, obviously, on the power of your scope and also the level to which you're attempting your ID. I've ID'd Griffon Vultures at a similar range to that mentioned by Simon (and probably a little further), but only if I assume they're not Ruppell's or Black Vultures! I've ID'd Starling on a water tower just under 1.5 miles from my home in the UK. I know that on other threads here people have claimed to ID similarly sized birds at even greater ranges (even to a point at which I doubt they'd be visible at all). Another consideration is 'jizz' in terms of flight or even flock action - a wheeling flock of Starlings would be identifiable at a far greater range than a single bird. Similarly the 'winking' black-white-black-white of a flock of Lapwings renders them identifiable at very long range,

 

[njlarsen]

I've ID'd Starling on a water tower just under 1.5 miles from my home in the UK.

I assume you missed the spotless starling among them 8-P

Niels

 

[John Cantelo]

I assume you missed the spotless starling among them 8-P

Niels

Nah, I saw it but suppressed it!

Actually in mixed winter flocks Spotless Starlings can stand out at a surprising distance since adults look inky black rather than greyish black (although I wouldn't like to say exactly at what range this is visible).

 

[Simon Wates]

Nah, I saw it but suppressed it!

Actually in mixed winter flocks Spotless Starlings can stand out at a surprising distance since adults look inky black rather than greyish black (although I wouldn't like to say exactly at what range this is visible).

Many many kilometres John - though you have to have had quite few years under your belt in Iberia first!

 

[dantheman]

However, as the temperatures are usually warm with some heat-haze and dust in the atmosphere it makes the long range images in the scope rather more tricky!

Heat haze = The Bane of the Long Distance Birder!

 

[dantheman]

Still waiting to pick up a Magpie on my distant 6.9km-away rooftops. In the meantime I can view some feeders outside a pink bungalow over a mile away - had some tit sps today, presumably Blue Tits on size but just not enough to tell! Approx 1.85km away. Oh for that zeiss scope with the 100x eyepiece ...

 

[lewis20126]

That "8.30pm Royal Tern" was (apparently) so far away the bill colour could not be seen. I've seen many before and since (including Jan 2012) and reckon it must have been at least 3km away. The orange bill is detectable through a good scope at at least 2.5km, perhaps more.

cheers, alan

 

[Morg]

When I lived in the hills of North Wales I used to scope the Dee Estuary (10 miles distant) for Bewick's or Whooper Swans but never managed to see any. From that same spot, the mountains of the Lake District are visible in perfect conditions (100 miles) - but I've never managed to pick up a Golden Eagle either!

Geoff

 

[DMW]

It's about 15 miles from the NW tip of Jersey to Sark, and during seawatches on clear days it's possible to see people on Sark.

It's also possible to indentify adult Gannets flying close to Sark: I would guess at least 12 miles away. Of course, there could be a Cape Gannet or two involved!

 

[dantheman]

That "8.30pm Royal Tern" was (apparently) so far away the bill colour could not be seen. I've seen many before and since (including Jan 2012) and reckon it must have been at least 3km away. The orange bill is detectable through a good scope at at least 2.5km, perhaps more.

Don't know about dodgy rare terns, but I can spot a can of worms at about 50cm ...


Tbh, surely light conditions must play a part? - (direction of light, cloud cover, time before sundown etc ...) sometimes I have trouble picking up the red legs (allowing for variability) of the Redshank I can see at 1.2km ...

Admittedly if you can't get the bill colour, the rest of the bird must be pretty indistinct also - comes down to confusion species at range again I guess.

 

[Tideliner]

I have IDed displaying honey buzzards at about 3 miles. Would not like to split them from commons in level flight at that range though.

 

[halftwo]

Interestingly on patch in summer watching Hobbies disappearing in the distance we estimated (v roughly based on speed estimate x time) and reckoned they were visible at more than six miles, however, if we had seen the speck at that range, rather than watched it into distance, it wouldn't have been id-able at more than 3 or 4 miles.

 

[John Cantelo]

Interestingly on patch in summer watching Hobbies disappearing in the distance we estimated (v roughly based on speed estimate x time) and reckoned they were visible at more than six miles, however, if we had seen the speck at that range, rather than watched it into distance, it wouldn't have been id-able at more than 3 or 4 miles.

I can't help thinking at calculating distance in this way is inherently open to a very wide margin of error.

Of course what you can make out on birds at such a distance depends on whether you were watching with or without out optics (you don't say). I find I cannot see Hobbies beyond the 'tip' at Stodmarsh when viewing from Grove Ferry (c3 miles) with the naked eye. I can just about make out small dots at this range with my x8 bins, and larger dots in my x30 scope. On shape/size I find them impossible to distinguish from swifts/hirundines (presumably slightly closer but it's hard to say with high flying birds) at this range through the bins or scope. However on flight characteristics (esp. the slight hiatus as Hobby catch aerial prey with their claws vs swift/hirundines "fly through" technique) I find I can pick out Hobbies with some confidence. Canterbury cathedal - just viewable from Grove - is six miles away and I would say at such a range - even through a x30 scope - Hobby would not be detectable. There are usually plenty of feral pigeons around the tower and I'm pretty sure I've ever seen them from that range,

 

[Bird_Bill]

Made a post above about seeing trumpeter swans at over 2 miles with naked eyes. Checking with google earth,was 2.06 miles.Knew where birds were,knew app. when they were coming off the ground.Knew where they were going. Being able to "pre-set" means everything.With Trumpeters its no problem to pick them up 2 miles out in standard atmospheric conditions,by eye.Providing one's assured its going happen.Very large,very bright white conspiculous birds though.

(not exactly "birdy" but maybe relevant)
Be interested in hearing from (former?) members of HMRN,regarding signal flags aboard ship.
Pretty much standardized in size and not very large.
Optics almost always used in some very severe conditions,what might be average distance.
Establish a bench mark if you will.