Saturday, 9 August 2025

A bumper catch on 3/8/25

What a day! We started early, meeting at the Discovery Hut at 0430hrs for our 3rd attempt to catch Sand Martins in front of the Sand Martin bank. Unlike on the previous sessions, as we walked the nets out in front of the bank, very few birds emerged from the holes into the nets. As it was so quiet & there were seven of us (the most for years!), we decided to set some nets in the reed bed where we'd caught well a few days earlier. 

We planned to set six nets in the reeds, but after one quiet round, numbers started to increase & we never managed to put up the sixth net. Meanwhile, the Sand Martin catch also improved, with plenty of re-traps. 

The team in full flow...minus Doug who was watching the Sand Martin net

As usual, we didn't leave the Sand Martin net up for too long to minimise disturbance. Despite the quiet start, with only five or six birds as we walked in, we ended up with a total of 52 birds from the bank net, 35 adults & 17 of this year's young, all re-trapped birds apart from one adult & one juvenile.  Presumably the youngster had come in to roost from another colony as we're pretty sure we've ringed all the young hatched in the wall. Later in the day we also ringed one brood of four young, things are definitely slowing down in the wall!.

It was interesting that some of the young were captured together with their siblings, presumably as they were leaving a nest hole as they were extracted from the wall side of the net. Unless there's a reason to suspect that the young from a nest box haven't fledged, when completing nest records, an empty box is usually shown as a successful outcome. It was particularly nice therefore to catch APC2977-APC2980 together, which is the whole brood ringed (by me!) from box G28 on 13th July, proof that that particular brood had indeed fledged successfully.  At least two of the young were still using the nest box on 24th July, but had fledged by 31st July. Interesting to see that they are staying together & roosting in the bank, although we can't say for sure that they're still using G28. At the end of the project the data will be analysed more thoroughly & hopefully some more interesting findings will emerge. 

The brood in G28 on the day of ringing (13/7/25)

Two of the brood still present 24/7/25

Two other birds were caught in the Sand Martin nets, a Sedge Warbler & a Kingfisher. As Doug was constantly monitoring the nets, he saw the Kingfisher fly across the pond & into the net. His description: "it came in like a bullet & almost looked like it was heading for one of the holes!". A quick check on Google revealed that although not common, Kingfishers are known to predate Sand Martin nests, taking eggs & young. We have had a couple of missing eggs & young from the wall, so maybe a Kingfisher was responsible, although probably not this one as it was a youngster....unless it had learned the trick from its parents having been fed them as a chick!

Kingfisher....dark breast band & dark tops of its feet indicate a young bird (age code 3)

Lack of pale area on lower mandible indicates a male

Meanwhile, the nets in the reed beds were getting very busy, with plenty of Sedge & Reed Warblers & Chiffchaffs migrating through, plus a good variety of other species, mostly young birds hatched this year. The juveniles included two more un-ringed Sand Martins, like the one from the wall, presumably a visitor from another colony. 

At first glance this Chaffinch looks like a female, which is duller than the male. However, a closer inspection shows some brighter pink feathers appearing on the breast, growing as part of the post-juvenile moult, when the bird replaces the feathers grown in the nest with the adult type.

Chaffinch, a young male (age code 3J...still mostly in juvenile plumage)

Brighter pink breast feathers indicating this is a male Chaffinch. 

We also caught a young Robin moulting into its adult red breast. It had also moulted its juvenile inner Greater Coverts & was replacing them with the adult type which at the moment are just small tufts emerging from the feather sheaths, otherwise known as being 'in pin'. Often the juvenile Greater Coverts have distinct orange coloured 'thorns' along the shaft (see post on 26/9/24). However, this bird only has a very small amount of orange at the tip, so the background colour of the feathers will be more important for aging this bird once it's finished its post-juvenile moult. 

Robin undergoing post-juvenile moult, changing mottled feathers for red ones


Juvenile Robin wing

We also caught several young Goldcrests. The one pictured below was still mostly in juvenile plumage but was starting to grow its crest...which looks orange indicating that it's a male. 

Goldcrest growing its crest

We also caught three 'controls' ie birds ringed elsewhere.
  • A juvenile Sedge Warbler ringed at Teifi Marshes in Ceredigion Wales on 9/7/25. 
  • A Chiffchaff that had been ringed further up the Axe Valley at Colyton Sewage works by Mike Tyler on 22/7/25.  
  • A juvenile Reed Warbler ringed at Oxwich Marsh, Swansea , Wales on 10/7/25
Also, one of our juvenile Sedge Warblers that was ringed on site on 1/8/25 & re-trapped on 3/8/25 was then caught by the Swale Ringing Group at Spitend Marshes, Kent on 6/8/25. 

One unusual incident of note occurred mid morning. Two Roe Deer were seen running into the reed bed. On reaching the far net, it was found lying flat on the ground, with a guy & peg stuck high up in a tree on the far side of a stream. A large deer-sized hole was also found in the bottom shelf. Luckily the few birds in the net survived unscathed. 

It had been a long, exhausting & productive session. Although we'd started with seven of us, numbers gradually dwindled as people had to leave, and for the last few hours it was just Neil, Jan & myself, catching the last birds at 1500hrs & finally leaving the Wetlands at about 1600hrs having processed 217 birds!

The weary die-hards! Seemed silly to stop whilst we were still catching!

Results for the reed bed:


Ringed

Re-trapped

Control

Blackbird


3


Blue Tit

6

3


Cetti’s Warbler

3

1


Chaffinch

3



Chiffchaff

13

2

1

Dunnock

2

1


Garden Warbler

1



Goldcrest

3



Goldfinch

5



Greenfinch

9



House Sparrow

5



Kingfisher 

1



Reed Bunting 

2



Reed Warbler

33

5

1

Robin

2



Sand Martin

2



Sedge Warbler

31

6

1

Song Thrush

1



Whitethroat

1



Willow Warbler

6

1


Wren

5

1



134

23

3