Wader Fest

It was hard to resist returning to the Presa Centenario yesterday. Some heavy downpours had likely dropped a fair few waders onto its shores. I opted for a walk around the North shore for the first time, not knowing what surprises were held in store for me. Straight away I could see that the Wilson's Phalarope numbers were up. I scanned the reservoir from the dam and picked up 1080 straight away, with bigger rafts in the distance.

The shoreline was dripping with smaller waders as well. Baird's Sandpipers were the most numerous (450 scattered around), but there was also a noticeable increase in the number of Least Sandpipers (40+). 6 Semipalmated Plovers scuttled along the rocks, a bit of a bonus, considering their range according to Howell and Webb. Beginning to realise that the range maps in my book are fairly inaccurate, probably due to lack of observer coverage in inland Mexico. Next up were good views of a Stilt Sandpiper, providing an interesting comparison with the first of the 5 Lesser Yellowlegs that I picked up.

There was an increase in the number of American Avocets to 6 and also good numbers of Black-necked Stilts. Over 100 White-faced Ibises fed on the edge, but the most spectacular aspect of the day was the Swallow migration I was witnessing. They were there in there tens of thousands. Counting them accurately was beyond my skills. At one stage, I picked out a distant Peregrine

doing the rounds, and as I put my scope to it, I could see it was carving through a sea of Swallows - much like the footage you see of Falcons picking through the millions of Bats that leave their caves.

I'd just picked out a female Green-winged Teal when another swarm came into view. Midges. Ure was about, no doubt about that. I'd obviously stumbled upon their breeding grounds. For about 5 minutes, I had to charge through endless swarms keeping my head low and using the scope as protection. I couldn't stop to properly check out an interesting Woodpecker in the cactii and an even more interesting mammal running away from me - it looked like some kind of gopher!

Eventually through the midges, I had a chance to scan the lake again. Huge numbers of Shoveler (1200), 6 Pintails and plenty of Mexican Ducks. The B.W. Teals, Eared Grebes and the likes, though were obviously sticking to the reedy vegetation on the far shore. 6 birds came blogging along very close in shore. I got them in the bins and realised I'd picked up a group of American Black Terns. Quality. You never know what's going to turn up at the reservoir.

Part of the Phalarope raft

The thunder clouds were gathering so I decided it was time to head back. I'd got about 20 metres and had just flushed a nervous Hare before the rain started. It was proper rain as well. I was quickly drenched, but at least it quietened the midges down. When I finally reached the shelter of the dam, I opted for 1 last scan in case the rain had put anything interesting down. Result. 2 American Snipes probing away along the water's edge. Also, a different 'Peep' amongst the Baird's and Leasts. Reading Sibley had paid off, I knew it was another lifer - a Western Sandpiper.

Waders of the reservoir so far (max numbers):

Baird's Sand (450),

Western Sand (1),

Least Sand (40),

Stilt Sand (1),

Spotted Sand (25),

Lesser Yellowlegs (5),

B.N. Stilt (130),

A. Avocet (6),

A. Snipe (2),

W.Phalarope (1650),

Killdeer (70),

Semipalmated Plover (6).

and whatever else I've missed!