It was raining birds 50 years ago today

What happened at Minsmere on 3 September 1965 has gone down in history as one of the most remarkable ornithological events ever in the UK. I wasn’t even alive then, and can hardly imagine the enormity of what actually happened, but I do know that, 50 years on, it is unlikely that such an event will ever be repeated.

Over the years, Minsmere has, of course, been host to an incredible number of unexpected sightings. July’s albatross, the humpback whale two years ago, and last summer’s yellow-legged tortoiseshell are just three recent examples of species turning up that took everyone by surprise.

But even they pale into obscurity alongside the infamous events of September 1965. To help me to tell the story, I’ll quote some phrases from Minsmere: Portrait of a bird reserve by Bert Axell, Minsmere’s warden at the time. There had been an anticyclone over Scandinavia the previous evening creating perfect conditions for migrants heading south over the continent to become displaced.

“At 1.10 pm, the wind shifted suddenly to the south-east and the rain increased to a downpour. The remark ‘The wind has changed, this will bring some birds’ had hardly been made and agreed when we saw redstarts and wheatears land and skid on the wet tops of the cars outside.”

“The grass car park became a ... shallow pond into which began to drop dunlins and wood sandpipers ... the scattered bushes ... began to fill with small birds. Easily the most numerous were redstarts, garden warblers and pied flycatchers.”

Redstart by Jon Evans

The weather conditions had contrived to produce an incredible fall of tired, bedraggled migrants. Bert continued: “Later that evening our combined reports indicated that, from within the 100 acres of marsh which we were able to inspect, no fewer than fifty-two species of birds had come in over our three-quarters of a mile of coast ... 7000 redstarts, 4000 wheatears, 2000 garden warblers, 1500 pied flycatchers, 750 whinchats, 500 willow warblers, 400 robins, 300 spotted flycatchers and 200 whitethroats. Terns could not be counted. Flocks of 150 whimbrels, sixty greenshanks and thirty wood sandpipers were counted on the ground.”

It didn’t end there, with more birds arriving that evening, so the following day they counted “25 wrynecks, 25 bluethroats, two or three each of dotterels, tawny pipits, icterine warblers and ortolan buntings and ... at least 200 000 foreign wheatears, redstarts, warblers and flycatchers.”

In fact, while there was a fall of migrants along the entire east coast, it was soon clear that a short section of the Suffolk coast had attracted the lion’s share of these tired migrants, and the great fall continued into 5 September.

Within the 18 miles of the Suffolk coast, from Minsmere north to Lowestoft, it is estimated that during those three days alone more than half a million migrants made landfall. This included 250 000 redstarts, 100 000 wheatears, 4000 whinchats, 3000 garden warblers, 1200 willow warblers and tens of thousands of pied flycatchers.

Pied flycatcher by Jon Evans

Why did so many birds arrive in such a short space of time? It was the result of a unique set of weather conditions combining to encourage migrants to depart from Scandinavia, only to become disorientated and swept off course. To be concentrated in such a tiny area is extremely unusual.

Birdwatchers still dream of high pressure over Scandinavia in autumn, as this creates the perfect conditions for drift migration. Such weather conditions continue to attract scarce birds such as wrynecks, red-backed shrikes and barred warblers to our shores alongside commoner migrants like redstarts, wheatears and warblers.

So why can I so confidently say that we will never again experience the sheer numbers of birds literally falling from the sky as they did in September 1965? Because across Europe, as in the UK, populations of many of these species have declined so much that there simply aren’t likely to be so many birds moving at the same time.

To help to illustrate this, the weekly review on Birdguides for 18-25 August 2015 refers to a “spectacular fall of pied flycatchers.” Yet, although thousands arrived along the East coast on Monday 24 August, the largest single site count was about 230 at Spurn in East Yorkshire. Good numbers of wrynecks were also associated with this fall, but spread along the entire east coast.

Here at Minsmere, we’ve been celebrating a “good week for migrants”, yet the highlights have been one wryneck, one red-backed shrike (present today for its third day), several whinchats, wheatears, redstarts and pied flycatchers. Apart from the latter, these species all nested commonly in Suffolk until at least the 1950s, but only redstarts and wheatears maintain a tenuous hold in the county as breeding birds today, and wrynecks and red-backed shrikes no longer breed regularly in the UK at all.

In fact, today’s weather conditions briefly hinted at another fall, especially when light showers arrived at lunch time, but apart from unusually large numbers of pied wagtails and house martins, there was no obvious sign of new arrivals. Clearly, there was to be no repeat of the amazing events of 50 years ago.