I CAN'T feel it co-ming in the air to-night. Oh Lor-ord.

May 30, 2018  •  Leave a Comment

I was texted by my Chicago-living sister a couple of days ago.

She asked me (or should I used the modern parlance and say "arksed me"?) "Where were the swifts [this year]?"

I replied back and said... "They're here". (As they are - and have been for a fortnight or so now).

I'm guessing (but with history on my side) that she had seen various news reports from British TV (she still watches British TV in the States) and on the web that our British avian Spring migrants were missing in action this year.

And to be fair to my sister, there are quite a few reports of this, worrying phenomenon (or ,I suppose, lack of a phenomenon) over the last week or so here.

I rarely watch Spring/Autumn/Winterwatch these days, as rather like the Harry Potter books,  I regard Springwatch to be an absolutely wonderful thing for kids, but not (at all) for adults - but I did catch a few minutes of the first (I think) Springwatch TV program this year (a couple of days ago) and saw Chris Packham suggest that "our swifts had a couple of DAYS to get here now or they'll be too late to breed".

Then on BBC Breakfast this morning I was informed by the newsreaders (the almost unwatchable Charlie Staid Stayt and Naga Nunchaku Munchetty) that (and I quote) "There has been a DRASTIC fall in the numbers of swifts arriving here this year, from Sub Saharan Africa".

Luckily BBC Breakfast then cut to a live report from a garden in Bristol, where someone like me, Mark Glanville, had transformed his house into a swift colony and told the reporter that all of his swifts had returned and he even had a new swift turn up. He then did suggest that "this was bucking the national trend this year" though admittedly.

A sensible chap from the BTO then fleshed out the rather sensationalist headline from the BBC though with a few very scientific thoughts - "swifts are in decline generally, they're difficult to survey, they may just be late" etc.

 

Regular readers of this marvellous *cough* blog, will (of course) know that I am besotted by swifts and look out for them after St.George's Day each year, having desperately missed them for the previous nine months or so.

And yes.... "our" swifts were later than usual here and fewer in number. But nothing that I thought that was particularly notable. They were perhaps a week later than I'd have bet on  -  and maybe down by 25% in predicted numbers (but then again, I'm attracting them to a part of the country they are CERTAINLY not used to returning to at present (a post war town) so numbers and return dates so vary considerably here).

I also should say that for the WHOLE of April (well... for 4 Sunday mornings in the month), I (and twice my 5 year old son with me) walked down a country lane that I know well as a hot spot for swallows... to welcome in the first swallows of the year. The long and short of that was we didn't actually see a swallow in April. (It took them until May to return - and that certainly is a fortnight or so late for them).

 

That all said, I thought I'd look at the quite excellent BTO Bird Track website, to see just how our avian Spring migrants were faring this year - and was it just swifts that were reported to be arriving a fortnight late or as the BBC shouted at me this morning, basically NOT AT ALL.

I reproduce a few sightings graphs from the excellent BTO Birdtrack website below; a few being 16 or 17 of some of the more common of our Spring migrants that I could think of, off the top of my head.

You'll see the historic data (red lines) and this year's data (blue).

Please do note though, that these graphs don't actually represent the EXACT numbers of birds returning to our shores, but as a proportion of how many times they've been seen, recorded and most importantly of all, then REPORTED as a (specific!) species on a list of all species by pretty-determined (on the whole) birdwatchers, or as they call themselves these days, "birders" (cringe).

I have HUGE misgivings (generally) about "phenology" and "citizen science" - it is open to massive abuse and huge error (in short, it really isn't at all scientific) but I put my large misgivings aside for something like BTO bird-track (which does appear very rigorous and robust) rather than something like "the Great British garden birdwatch" which again, is superb for kids (to get them into appreciating garden birds) but that really is all.

Anyway.

I digest digress.

Have a peer at the graphs below - and you'll see a pretty stark pattern emerge.

I'll give you my two-bobs worth after you've had a peer.

I apologise for uploading a set of graphs that you may have to enlarge to read properly (if you don't know how to... hold down CTRL on your keyboard and spin the wheel on your mouse forwards (to return to normal, hold down CTRL again and pull your mouse wheel back)).

OK.

For what it's worth.

A rundown of the above.

  • Swifts - two weeks "late" and perhaps (but not conclusive yet) fewer numbers returning. 
  • House martins - fewer numbers (it seems right now).
  • Wheater, whinchat, sand martin, nightingale and cuckoo - not late as such, but fewer numbers, it seems right now.
  • Turtle doves - FAR fewer numbers. Will ANY return next year?
  • Garden warbler and common tern. Not really much to talk about here. About normal really. Perhaps a little fewer than normal.
  • Spotted flycatcher - see swifts. At least two weeks late and perhaps FAR fewer numbers than "historically-recorded".
  • Swallow and redstart. A little late and a little down on numbers.
  • Finally - nightjar and reed warbler - on time (or even early) and normal (or more!) numbers returning.

 

 

The overwhelming pattern from the above is everything (almost everything) is two or so weeks late and returning in fewer numbers - the obvious anomalies to me at least being nightjar and, I suppose, reed warbler.

I should at least point out again here that this data represents percentage of birdwatchers' reported tick lists that contain these species above on any week - rather than ACTUAL numbers of birds  - and as such you could easily explain  the nightjar anomaly quite easily.

Nightjars are wonderful, mysterious birds of mainly lowland heath. They arrive in May (often) and on warm, still(ish) nights in May they can be heard "churring" on these lowland heaths at dusk.

Until the last few days, the UK has experienced quite superb weather throughout May - I'm typing this with a healthy tan and we're not even into June yet. We've had many days of well above average temperatures here since mid April (we've hit 30C twice in the last few weeks).

This will have been a) heaven sent as far as nightjars are concerned and also b) heaven sent as far as birdwatchers walking lowland heaths at dusk to HEAR nightjars are concerned. It really is no surprise at all (to me) that the nocturnal, heat-loving nightjar is the exception to the rule as far as the pattern above is concerned.

 

But what OF the pattern demonstrated so starkly, above?


Why are (pretty-well) all our Spring migrants late?

I haven't much idea to be honest, but you'll hear many lazy journalists point to the "Beast(s) from the East" in March as a reason.

That's nonsense though, to be frank.

Whilst meteorologists insist we all call the start of Spring as being March 1st - in reality, Spring doesn't really 'start' (as such) until the vernal equinox three weeks into March and our Spring migrants don't really start errr.... migrating to us..... until then. At the earliest really.

No animal (bird or otherwise) can, (despite our hysterical tendency to vomit up old country myths/sayings and wallow in much anthropomorphism,)  PREDICT weather and take proactive action to avoid "beasts from east" etc.
And anyway, the "beast(s) from the east" as far as astronomical (day length) Spring is concerned were in Winter!

No... the weather over the UK in Spring proper (from late March onwards) was pretty good. VERY good in fact you might say. 30C in April?!

If there are reasons that perhaps millions of birds didn't make it over to our shores in their historically-recorded average window, those reasons would have FAR more to do with environmental conditions on the continent or in Africa than weather conditions here.

Perhaps the good (food-rich) weather conditions in these birds' wintering grounds was extended. Perhaps their journey across Africa was interrupted by 'bad' weather. Or perhaps their journey across Europe was similarly disrupted.

We all know about the dangers ALL these birds face from the guns lined up all long the Mediterranean - and this will continue to affect all these birds - particularly birds which are critically endangered and fly during the day - like (see above) the Turtle dove.

 

That's all I have to go on really.

It IS true (or at least seems to be) that the vast majority of our avian Spring migrants are about (on average) two weeks late due to weather elsewhere. And often have arrived (and will do) in fewer numbers than historically-recorded. These weather events (not historically normal) might be more and more prevalent in years to come - and that may well be because of "anthropogenically-accelerated global warming" (otherwise now known simply as "climate change").


Right.

That shallot for now.

I hear at least two swifts outside screaming at the house - so I'm off out to gawp at them.

Have a lovely evening....

TBR.

 

 


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