Do birds know the rules?? (1 Viewer)

I was contemplating the situation re: the Squacco Heron which was down in the south-east last week......

First reported sighting was in Dungeness (I'm thinking first UK landfall)
2nd day it was at Reculver in North Kent
3rd day Abbington Reservoir in Essex

So I'm thinking.... "Bet it turns up at Minsmere or somewhere on day 4..."

It didn't of course.... never been seen or heard of since, so anybody's bet as to what might have happened to it.

Anyway........ Having thought "Minsmere", my almost immediate 2nd thought was "Hang on. What if this bird doesn't know the rules, and doesn't realise that it's supposed to fetch up at some well known birding hot-spot, where dozens of birders will be stood around waiting to id it."

This led me on to wondering whether most exotic birds are actually spotted (because most of the good habitat is identified/protected and well watched) or do we miss the vast majority just because there aren't enough birders to go round.

Even a well-watched County like Kent would only have a tiny proportion of its countryside watched by birders, I should have thought.

Back to the Squacco...... I guess it could still be happily making its way North, but just making sure it steers clear of RSPB reserves and the like (I guess it could just as easily be heading back to the Med, or have come to a sticky end...)

Any thoughts??

I would think that a very large number of birds go unfound in the UK... you've only got to hear the tales about how some rare birds are found to be sure of that. The golden-winged warbler in 1989 (still the only western pal record) was found by a birder when he was popping out to post a letter... how many other birds are skulking about in bushes that we walk/drive by on our way to the shops or even worse to a birding site.

Also just look at the birds that were found in gardens last week - dark-eyed junco, white-throated sparrow, black-headed bunting and one of the squaccos - just think what may have turned up in the gardens of non-birders and just been seen as another bird at the bird table.

As for the squacco, if it could find it's way to Norfolk that would be very useful

Apologies to refugees from uk.rec.birdwatching, who may have seen the following before since I posted it there about 18 months ago.

In March 97 BB published an article by Pete Fraser called "How many rarities are we missing?". Fraser analysed the BBRC statistics for 1958-92 and found that, despite steadily increasing observer coverage over the years, there wasn't much variation in the percentage of rarities found at weekends (44% in 1958, reducing to 40% in 1992). Sites well-watched by weekend visitors from the big connurbations showed the most weekend bias; those covered more exclusively by local observers showed the least.

He then devised a model that ran thus: Assuming that no site is covered with 100% daily efficiency, the rarities found on any given day will consist of (1) a percentage of that day's arrivals, (2) a percentage of the previous day's arrivals which were not discovered then and (3) a (small) number which arrived even earlier, also previously undetected. At well-watched sites he reckoned that 90% of all rarities were discovered, of which 40% were recorded only on one day. At less well-watched sites 70% were recorded on one day only, probably because with less coverage it is easier to lose track of the birds and because fewer are found on the day they arrive. He ended up with an estimate that 60% of rarities remain beyond one day; of these 70% are still present the next day, 70% of those the day after and so on. Then it was a question of first finding the best fit between the model and the statistics. In the Isles of Scilly the reduction in numbers of birds found on Monday pointed to an efficiency of 92% on Sundays and less effort on Saturdays (76%) than on weekdays (78%) - which seems logical since Saturday is the big change-over day there.

In 1990-94 the average number of rarities discovered each year was 755, while, at a conservative estimate about 800 were missed. The rate of discovery for passerines, near-passerines and waders was significantly less than for larger birds (unsurprisingly). For passerines, the percentage missed in different areas were:

Fair Isle 11%
Scilly/Cape Clear 11%
Orkney/Shetland 45%
South Coast 53%
East Coast 57%
Elsewhere 60%

What Fraser didn't cover was whether there are any differences between the different seasons - a pity since, on average, autumn birds stay longer than spring ones and winter ones longer still and I would have thought this would be reflected in variations in the finding efficiencies.

Anyway, it seems that we're finding less than 50% of the rarities. Get out
there, folks!

Hi Postcard,

I was thinking that my thread had sunk without trace.....

Yes, logic would suggest that the countryside is fairly sparsely covered, so most of the birds must get away with it (as it were...)

Does make you wonder though, when the Squacco Heron chooses to show up in 3 of the most watched areas of the South-east in 3 consecutive days.

As regards the Heron, if it had carried on as before, it would have made it into Norfolk by now.... No way of knowing what happened to it I guess. Maybe the most likely scenario is that it came to its senses and did an about-turn and headed back to France....

Hi Jason,
Did Pete Fraser also take into account either of these facts(and these are certainly relevant in a country with a low observer base like Ireland):

1)What about all those good areas that are rarely checked,if ever?

2)Surely his article makes the assumption that all rarities are equally easy to identify,which clearly isn't the case!Some species would be so tough that only a small minority of birders could correctly ID them in the first place!

Harry

Hi Harry. It's so long ago since I read it that details are very hazy, but I don't think he made allowances for either of these factors. I think he was merely analysing numbers (he's the BBRC's statistician, after all). I seem to recall him admitting that his findings were only a crude indication.

Hi Guys,

Thanks for the post Jason - it'll take a while to digest that!!

If I'm reading it correctly, this article just talks about regular 'birding hotspots' as it were...

The Heron's 2nd stop was nr Reculver which is a popular and well watched area, but just a few miles to the West is Cleve Marshes/Graveney Marshes just to the East of Oare. Now, I've never heard Cleve/Graveney mentioned in any birding reports (but it looks like a similar habitat) so I assume that it isn't well watched.

If it had turned up there, I guess its chances of being spotted would have been a bit reduced...

Ruby said:

The Heron's 2nd stop was nr Reculver which is a popular and well watched area, but just a few miles to the West is Cleve Marshes/Graveney Marshes just to the East of Oare. Now, I've never heard Cleve/Graveney mentioned in any birding reports (but it looks like a similar habitat) so I assume that it isn't well watched.

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Reculver is watched by a highly experienced birder on virtually a daily basis. So, looking at Jason's post, it seems reasonable to assume that a high percentage of rarities will be picked up. But equally if it had turned up at Cleve/Graveney it would almost certainly would have gone unnoticed.

I know that most of the major birding areas in Kent are well covered but in such a large county with its proximity to France I am sure that loads of rarities go unseen.

Hi Ruby

Guess I'll have to read that article again when I've got time.

I'm sure you're right about the Squacco. The last one I saw was on a small pond that I seriously doubt is on the average birder's itinerary. If it hadn't been that the Secretary of the BBRC lived nearby...

Edit: I think that illustrates Robin's point too.

There are so many rarities missed that, if they were seen, most of them wouldn't be rarities anymore. If that makes sense.

I would say that the majority of long-staying waterbirds in well-watched parts of the country (excluding really skulking species like crakes) get picked up. Otherwise, we're just scratching the surface.

Fifebirder said:

There are so many rarities missed that, if they were seen, most of them wouldn't be rarities anymore. If that makes sense.

I would say that the majority of long-staying waterbirds in well-watched parts of the country (excluding really skulking species like crakes) get picked up. Otherwise, we're just scratching the surface.

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I find this quite encouraging...... just keep your eyes open and who knows what might turn up in the most unlikely to places...

Just thinking of the number of birds which I have seen as 'one-offs' in my suburban garden....

Fifebirder said:

There are so many rarities missed that, if they were seen, most of them wouldn't be rarities anymore. If that makes sense.

I would say that the majority of long-staying waterbirds in well-watched parts of the country (excluding really skulking species like crakes) get picked up. Otherwise, we're just scratching the surface.

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Agreed. I reckon that as soon as you are more than a mile (or even a half-mile) from the coast, about 99.8% of rare birds don't get found.

Michael

In Iceland we see the smallest tip of the iceberg. It's a country bigger than Ireland but with no more than 15-20 people actively looking for birds on a good weekend in October, backed up by a loose network of non-birders who report strange things to birders if they stumble across them (Least Flycatcher, Varied Thrush, Green Heron all good recent examples). There are hundreds if not thousands of kilometres of coastline which receive no coverage whatsoever although admittedly we have fewer trees for them to get lost in. Just think how many eastern rarities the Finns lose in their impenetrable forests!

As an example of what we are missing we always cite the case of that October morning in 1967 when a farmer in south-east Iceland, the only birder in the country at that time, saw in his small garden Wood Thrush, Scarlet Tanager and Black-and-white-Warbler. If that was in south-east Iceland, what was in the south-west, especially on the Westmann Islands? The mind boggles.

E

I concluded, from reading the Fraser paper, that birding the Lincs and Northumb coast on a Thursday will be your best bet for finding a rarity. Norfolk on a saturday will give you least chance. Scillies in October.... forget it!!!!!!!!!!

tom mckinney said:

I concluded, from reading the Fraser paper, that birding the Lincs and Northumb coast on a Thursday will be your best bet for finding a rarity. Norfolk on a saturday will give you least chance. Scillies in October.... forget it!!!!!!!!!!

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Fife coast on a Wednesday worked for me, and it was Fife coast on I think a Monday for Fifebirder ...

Rob