Today's trip to Aviemore was nearly called off because of a very poor weather forecast. In the event, the only problem was a very strong south west wind (which made the going pretty tough in a couple of places and rendered bird calls virtually impossible to hear). Thankfully, the heavy rain that was predicted failed to materialise.
Most of the journey north took place in darkness. However there was sufficient light to reveal a Grey Heron at Netwonmore and a Kestrel at Kingussie. In Aviemore, a short walk down to the river opposite Cambusmore produced two Goldeneye and an interesting collection of corvids consisting of 120 Jackdaws, a couple of Carrion Crows plus one each of Rook and Hooded Crow x Carrion Crow hybrid. A dead birch tree there seemed to be supporting several types of bracket fungus.
The bus to Nethybridge produced tantalising but very brief views of big groups of mixed gulls, corvids and pigeons on flooded fields around Granish. Around 70 Rooks were in front of Deschar School and a single Roe Deer was at Mains of Garten. 
The original plan was to walk to Broomhill Bridge, then return to Nethybridge and follow the Speyside Way back to Boat of Garten. Instead, a different route back was chosen, along the north bank of the Spey.
Birds encountered along the Nethy included Chaffinch, Long-tailed Tit, Pheasant and two Dippers. Around 20 Mallards were disturbed from the Spey where the Nethy joins it and eight Teal flew by. A single Goldeneye was beyond the bridge and two Whooper Swans were further downstream. Three more Dippers were feeding by plunge-diving into the middle of the river and chasing eachother exhuberantly.
Heading west along the north bank, the waterside trees held various passerines including Blue Tit, Great Tit, Chaffinch and Treecreeper. One flock of Chaffinches held a single Yellowhammer. 
Birds on the river were difficult to see because of the low sun. However the commonest species was Mallard, with a few Goldeneye and a single Tufted Duck also present. Some small groups of Greylag Geese flew over and another large flock of Jackdaws was at Tullochgorum. 
Best sighting of the day probably  concerned the 33 Wigeon which were seen on a wide section of the river just east of Drumuillie. A Buzzard was also there.
Finally, arriving at Boat of Garten (via an excellent new footpath past the sawmill), a chilly Milton Loch held 27 Mallard, 15 Wigeon (whistling quietly) and six Teal. 

The illustration below (entitled "strathspey evening birches") is from Kurt Jackson (http://www.kurtjackson.com/).

 
The total bird list for the day was as follows: Whooper Swan, Greylag Goose, Wigeon, Teal, Mallard, Tufted Duck, Goldeneye, Pheasant, Grey Heron, Buzzard, Kestrel, Herring Gull, Feral Pigeon, Woodpigeon, Jackdaw, Rook, Carrion Crow, hybrid Carrion x Hooded Crow, Goldcrest, Blue Tit, Great Tit, Long-tailed Tit, Treecreeper, Wren, Dipper, Blackbird, Robin, Dunnock, Chaffinch and Yellowhammer (31 species).
Impressions of Strathspey in December.
The tops are back to being snow-free, but some of the bigger hills were starting to whiten in the course of the day.
The south westerly wind is a significant force in terms of the way it limits wildlife activity.
The ground is still soft, presumably making feeding much easier.
Many birds (including ducks, geese, gulls, corvids, finches and tits) continue to show flocking behaviour. 
Some species (Mallard, Teal, Wigeon) are already courting and pairing off.