Doncaster Nats at Fowlsyke Flash Wednesday 30^th October 2024:

We went on a MOUSE HUNT!

Weather: The sky was slightly overcast but the temperature was warm (11 to 14^oC.) with a slight south westerly breeze <15km/h.

The search team: consisted of CAH; Ian F; Gerri S; and David C.

Route: After visiting the population of Dwarf Elder (Sambucus ebulus) on the left of the path leading to the Viaduct (the colony is now beginning to spread downhill onto the Trans-Pennine trail), we followed the TPT down to the Don banks and walked east toward the open water of Fowlsyke Flash. Here we were joined on site by David C, who had legged it along the TPT from Sprotbrough.

The Site: The once numerous gaps onto the wetland site are now thickly overgrown with bramble, though we managed to find our way through to the dense beds of Reed Sweet-grass (Glyceria maxima) and commenced searching for mouse nests at 12 noon.

Results: Using gardening gloves to part the tall dense stems of the Glyceria, nests were located almost immediately. Over a period of 2 hours, some 9 nests were located, giving a find rate of [9 ÷ 2 (hrs) ÷ 4 (people)] = 1.125 nests per person per hour.

Only one nest looked as if it had been a breeding nest, the rest we referred to as single-occupancy ‘bivouac’ nests. All exhibited the weaving of longitudinally shredded leaves still attached to the grass stems.

Distribution: According to Dave and Ian, using the OS apps on their iPhones, all records were in OS Grid squares SK526996 (2 nests); SK525995 (6 nests) and SK525994 (1 nest).

Most were in the densest beds of Glyceria growing out of waterlogged ground around the edge of the site. As per earlier searches, some nests were in tussocks supported by bramble briars. None were encountered in the less dense beds growing in standing water.  Two atypical nests woven at ground level, where the vegetation at the edge of the arable zone, had been mown back and re-grown earlier in the season. One of these was in Glyceria and the other woven in what appeared to be a finer-leafed Couch Grass Agropyron repens.

Table of finds.

Table 1

Nest type	Height above ground	Heiht of plant	Grid Ref.
Nursery	24″	6′  3″	SK526 996
Single Use	32″	6′  6″	SK526 996
Single Use	36″	6′  6″	SK526 995
Single Use	36″	6′  8″	SK526 995
Single Use	39″	6′  3″	SK526 995
Single Use	32″	6′  3″	SK526 995
Single Use	14″	6′	SK526 995
Single Use	Ground	Mown	SK526 995
Single Use	Ground	Mown	SK526 994

Other sightings: Robin (singing); Blackbird. Birds flying over included Skeins of Pink-footer geese (very vocal) flying west at 10:55am; Carrion Crow; Wood Pigeon; Cormorant. As light was fading at 2:15pm two Ravens flew over, probably heading for Cadeby quarry, ‘cronking’ as they went.

Before we left the car park we had a quick look at the disused Cadeby Railway Tunnel where in previous years we have undertaken winter bat hibernation searches, finding the odd Long-eared Bat.

Thanks to the participants for making it a most interesting and enjoyable day.

C.A.Howes