Shufflers in freezing feeding frenzy

Feeding frenzy - Shufflers, Coot-muggers and a Great Crested Degree.

With a few inches of snow and an easterly breeze, I decided it was time to give Siri a go on my up-graded iPhone rather than get frozen fingers scribbling in the notebook. As I wandered around the valley, a summary of each site was carefully dictated before I headed home, hoping to find my day list magically appearing on my computer via iCloud. And there it was. Holyfield Marsh was particularly good. Apparently I saw a lot of Shufflers, 157 apparently. And also 13 Descenders, 350 Tufted Darks, 4 Snooze (3 drunks and a redhead), 15 Great Crested Degrees and a Yellow-laked Goal. I’m not sure whether I need to train Siri better or change my accent.

With large numbers of birds restricted to small areas of unfrozen water, the apparent heightened and frenzied feeding activity was interesting. Several groups of diving Coots not only had their associated kleptoparasitic Gadwalls (the ‘Coot-mugger’) but had attracted a range of other ducks and gulls. Nearby, a swirling mass of 60+ Shovelers, sorry Shufflers, continued to stir up and sift planktonic invertebrates from a small patch of water. Such feeding behaviour is typical of the Shoveler, but I can’t recall such a large group or such frenzied activity.

I had followed almost the same route around the lake back in the freezing conditions of January 1985. On that visit, the count of Smew reached a remarkable 40 birds (with at least 19 drunks), along with a Slavonian Grebe and 300 Wigeon. A Bean Goose (‘rossicus’ say my notes) had joined the adjacent Canada Goose flock but it eventually and illogically got dismissed as an escape. I think even Siri would have got that right.

To feed or not to feed?

The recent severe weather has been tough for Bitterns, with many being seen around the remaining areas of unfrozen water, frequently in unusual situations.  Bitterns traditionally suffer in such cold winters.  At least 17 sites attempted to feed their Bitterns, usually with Sprats or Sardines, during the coldest spell of weather and 8 sites report that Bitterns were seen taking the fish. See Steve Blain's video of a Bittern eating sprats  (or below) provided by local birders at Stewartby Lake.  At Leighton Moss, three Bitterns came to the feeding site regularly (about once every half hour), took some fish and then returned regularly during the day.  At most of the other sites, Bitterns were seen in the vicinity of the food and may well have taken it.  So it would appear that feeding in hard weather may help some Bitterns survive.  We feed Blue Tits, so why not a bird that is a conservation priority in the UK?


On the other hand, is this just another example of unnecessary human tinkering?  Will it make any difference at all to the population in the coming spring, or will it even hinder a natural dispersal of young birds to new sites?  What do you think?

Edit - In a rather low poll, 16 out of 16 respondents thought we should be feeding Bitterns.

Bittern eating sprats from Steve Blain on Vimeo.

What's happened to cold weather?

R-b Merg on the KGV, packed-in Tufties at Nazeing and Smew at Cheshunt.

What’s happened to cold weather? When we had it in the 80’s we were splattered in scarce grebes, divers, gulls and other stuff. This winter has been rather slow, a few Bitterns and Smew (but barely more than usual) and not much more so far. Okay, there were some Eider on the Girling today, and we are knee-deep in Waxwings, but overall it’s not like it used to be.

In early 1979, strong north-easterly winds precipitated a remarkable influx of, amongst other birds, grebes, divers, Smew and Goosander. Within a month my Lee Valley list included 12 Red-necked Grebes, 30+ Red-breasted Mergansers, 2 Slavonian Grebes, 2 Black-throated, 2 Great Northern and a single Red-throated Diver, 26 White-fronted Geese, Hen Harrier, 5 Long-eared and 6 Short-eared Owls.

Likewise, in early 1985, severe weather resulted in a massive influx of Smew (up to 40 at Holyfield Marsh alone), Scaup (9), Slavonian Grebes (5), Red-necked Grebes (4), Velvet Scoter (3), Long-tailed Duck, Bean Goose, Glaucous Gull, Shag and Hen Harrier. However, judging by the length of my notes, a Mediterranean Gull was the most exciting.

Is this current weather not blasting easterly enough, has climate change shifted the distribution of some of these birds, or are there just fewer of them nowadays? Or perhaps a bit of all three?

Cold weather refuges are critical for wintering waterbird populations. These may be provided by the larger, deeper waters of the reservoirs that rarely freeze, or by sites that have flowing water, such as the rivers or the sewage treatment lagoons at Rye Meads. The winter of 2008/09 provided an opportunity to record hard-weather effects in the valley during the short freezing spell in early January. At this time, up to 2,000 birds may have left the valley, with around 1,000 returning as milder conditions prevailed. Dabbling duck were mainly affected with losses of Gadwall, Teal and Shoveler but significant numbers of Coot also left. Birds also re-distributed; Gadwall concentrated on Netherhall GP and the King George V Reservoir, as sites such as Amwell NR, Holyfield Marsh GP and Cheshunt GP froze over.