West Nile Virus, or jet-lag? Dallas, Sept 2012

Texas is in the grip of an outbreak of West Nile Virus. Dallas leads the field in cases of the mosquito-borne disease and the authorities are enacting plans to spray insecticide from the air to reduce the numbers of adult insects. Ignorance on my part prompted me to make enquiries about the virus and the risks. I found that it has recently become endemic across the country and is borne by mosquitoes that have ingested blood from infected birds. I weighed the risk against the consequences, took the normal precautions, kept calm and carried on.

After visiting White Rock Lake (a WNV hotspot), I am suffering from disorientation, loss of cognitive function and a stiff neck. How would I know if my symptoms are a result of the virus or just jet-lag coupled with a morning’s warbler-watching? 

Using the Blue Line from Downtown Dallas, brings you to White Rock Station. At this time of year the walk to the lake and around the northern section leave you with the sun in your eyes for much of the walk. I had set the Singing Bridge as my furthest limit. Not very far to walk, but the walk passed through the best warbler habitat that I knew of within easy reach. Plenty of Tufted Titmouse kept up a soundtrack for the morning with Carolina Chickadee and Northern Cardinal easily recognisable by ear.

The first warblers came before I reached the lake, but I struggled to make a confident ID at the scene. In the end, I settled for Nashville Warbler mixed with a couple of Yellow Warblers. More migrants came at the small bridge at the most north-westerly extreme of the lake (at Google Earth ref;  32°51'2.38"N 96°43'45.20"W). It bounces uncontrollably when anyone jogs across it. I guess that’s the purpose of joggers eh?

A Warbling Vireo and Wilson’s Warblers were seen here as they fed from the myriads of mosquitoes. The path tracks for over 12kms around the lake and is busy with joggers and cyclists.  I recognised a couple of cyclists going round for a second and even third time as I ambled slowly along in a clockwise direction towards the Singing Bridge. There was very little out on the water, just a Great Egret and a couple of Mallard. The trees and bushes along the path were similarly quiet in the heat of a Texan, late Summer’s day that pushed the mercury past 40°C.

From the Singing Bridge, you can see into a small lobe of the upper lake. Among the Mallards were a single American Wigeon and a female Northern Pintail with her long, slim, elegant neck. As I turned to set out home, I noticed a bird hawking from dead snags on the north shore. It was a flycatcher with a long streaming tail. As I watched, it shuffled on its perch, revealing rose-coloured flanks and under-wing. Today’s lifer is a Scissor-tailed Flycatcher.

I retraced my steps along the path hoping to get a closer look at the Scissor-tailed Flycatcher, but by the time I reached it, it had turned into an Eastern Kingbird. 

Back on the bouncy bridge Wilson’s Warblers, Yellow Warblers and Warbling Vireo were thrown into a panic as a young Cooper’s Hawk came through. I wondered if the biting insects were bothering it, as it continually wiped its bill across its legs and looked to be biting its own toes.

The cycle trail leading back past the station still held a couple of surprises with a Summer Tanager putting in a brief appearance and a White-eyed Vireo that responded to a quick playback. The cycle trail continues along White Rock Creek.

There were plenty of mosquitoes. Best practise advice is to avoid areas of standing water. Cover up with long sleeves and use insect repellent. Be especially vigilant around dusk.

Birds seen; 31

American Wigeon 1, Mallard 45, Northern Pintail 1, Double-crested Cormorant 6, Great Blue Heron 1, Great Egret 1, Snowy Egret 1, Cooper’s Hawk 2, White-winged Dove 3, Mourning Dove 15, Chimney Swift 6, Red-bellied Woodpecker 1, Downy Woodpecker 2, Eastern Kingbird 1, Scissor-tailed Flycatcher 1, White-eyed Vireo 1, Warbling Vireo 2, Red-eyed Vireo 1, Blue Jay 4, American Crow 4, Carolina Chickadee 8, Tufted Titmouse 40, Northern Mockingbird 12, European Starling 2, Nashville Warbler 3, Yellow Warbler 6, Wilson’s Warbler 4, Summer Tanager 1, Northern Cardinal 6, Great-tailed Grackle 4, House Sparrow 8.

White Rock Lake

I would like to acknowledge JR from Dallas (yes, really!) for his website www.jrcompton.com in which he gives an account of the goings on at White Rock Lake. Dallas, Texas. His “Amateur Birder’s Journal” gave me the impetus I needed for a very quick visit on a very cold day. JR’s main topic of discussion of late on his site, is his fascination with pelicans in flight. So in tribute, I set out to follow his lead. As ever, my photographs failed to live up to my aspirations, which, given the bright, crisp light this morning, was a disappointment. I’m beginning to think it might be me!
The hotel I was staying in is the Marriot Quorum in Adisson. From behind the hotel, bus no. 183 rides into downtown and terminates at West Exchange in downtown Dallas. The tram/subway system connects here at West End Station. I travelled northeast on the Blue Line towards Downtown Garland. I alighted at White Rock and descended the steps to the junction of Northwest and Lawther. The journey took 1 hour exactly. A US$4 day ticket covers bus and train.
Diagonally across the junction, I picked up a cycle path that tracked south parallel to Lawther. It passed through an area marked as a wetland before passing under Mockingbird Lane. As I emerged from under the bridge, I could see White Rock Lake ahead of me.
There were lots of cormorants and gulls over-flying and a formation of seven American Pelicans crossed Mockingbird Lane heading North.
I had come to the lake at Bent Bridge in the northwest corner. A wintry scene greeted me as I approached the shore. The large trees at the waters edge were frosted white in keeping with the season and the chill. Actually, the cold muted the smell of cormorant guano that was the real reason for the effect. I will wager that it gets pretty high during the warmer weather. It was here that the light gained enough strength to allow me to start identifying birds. Carolina Chickadees were calling and Yellow-rumped Warblers flitted amongst the tangles. A Red-shouldered Hawk flew out from the woods on my left and joined a second in the cormorant roosts. The Pelicans were far out, but easily recognisable and accompanied by gulls and Double-crested Cormorants.
I began walking to my left in a clockwise direction. My time as ever was limited and a full circuit of the lake would not be feasible. My plan was to head towards Sunset Bay beyond Hidden Creek as my furthest point before returning back the way I had come. Anyone who has read this blog before knows that my estimation of time and relative dimensions in space is poor. Sure enough, I hardly made it as far as half of that distance, barely even 10% of the lake’s shoreline.
I had a couple of targets in mind this morning. Potentially a couple of red crayon birds were waiting for me in the cold. From the gulls, I hoped to winkle out a Boneparte’s Gull and from the sparrows, I hoped that a Harris’s would emerge.
Between Bent Bridge and Singing Bridge I scanned every Ring-billed Gull looking for a smaller, tern-like bird with a vestigial black smudge on it’s head from it’s summer plumage. The Song Sparrows were plentiful, but I was looking for something larger with a clear white belly and a pink bill.
To the north of Singing Bridge a patch of water huddled out of the wind, sheltered by trees and the Mockingbird Lane flyover. I had my first chance to try to emulate JR’s pictures as a number of pelicans took flight and passed back over the bridge onto the main body of the lake. There were also cormorants, Mallards, American Coots, Pied-billed Grebes and some Muscovy Ducks (probably feral). Up on the bridge, the wind was beginning to bite through my gloves and my fingers were already becoming painful.
There was some bankside vegetation along some stretches of the lakeside, which on a warmer day might have had me looking for dragonflies.
Grackles are common here with both Common and Great-tailed in constant view. Red-shouldered Blackbirds and Brown Cowbirds complimented my Icterid list.
Out on the water the birds roosted on boats and piers. I saw a small tern-like bird which turned out to be a tern. Beyond the boat clubs, a Downy Woodpecker landed in a tree right in front of me and posed provocatively. This meant having to take my hands out of my pockets to use the camera. It was becoming windier and beyond uncomfortable. A Fox Squirrel kept his arms in to his sides to preserve heat as he tried to warm up in the sun.
The pelicans were on the far side of the lake split into two groups. The furthest group was bigger but much more distant. The nearest consisted of around 45 birds. They were accompanied in the water by cormorants with gulls wheeling above. As I watched, they appeared to be heading towards me. Slowly but surely, they were moving eastwards across the water. The pelicans at the back would take to the air and reach across the wind to get to the front of the feeding flock. Thereby the front birds eventually found themselves at the back and took flight to get to the front again. It reminded me of pursuit cycling teams in reverse.
Standing still for a while had been a mistake. The cold and the wind had cut into me and I found myself constantly swearing and getting very cross with my useless fingers. It was time to bail out and head home. But that meant heading into wind which only served to make it worse. I was actually feeling quite distressed now.
Perhaps my resistance is getting lower as I get older. The savoury sharpness of a lifer was now tempered with the desire to feel my fingers again and my determination had faltered.
Back at Singing bridge, a low wall gave a respite from the wind and allowed me a few moments to warm in the weak sun. Some life had returned to my fingers, but I couldn’t stop swearing. I still had to cross the windswept bridge.
A patch of woodland beyond the bridge was alive with birds; White-winged Doves, Yellow-rumped warblers, Carolina Wrens, Carolina Chickadees, Song Sparrows and to my delight Eastern Bluebirds. I managed to get a picture of the bluebirds for my blogger-floggers who insist on “more pictures!”
At Bent Bridge the tangles and rank vegetation either side of it were busy too. At last I found a Mockingbird and a Northern Cardinal, both of which would have been a grave omission. I had seen very few duck today although I had been assured that they were there.
Just before reaching the junction of Lawther and Northwest I noticed high above, a Red-tailed Hawk being mobbed by American Crows.
On the return train journey, I headed towards Ledbetter to get into town. The frequency of bus and train is less during the day and the drive back to the hotel for pick-up took just over one and a half hours.
Our bus ride back to the airport produced as many as 20 redtails, perched on roadside snags and lamp posts.

Mammal species; 1

Fox Squirrel 6

Bird species; 35

Pied-billed Grebe 7, American White Pelican, 100, Double-crested Cormorant 400, Great Egret 2, Great Blue Heron 4, Mallard 25, Ruddy Duck 4, Sharp-shinned Hawk 1, Red-shouldered Hawk 4, Red-tailed Hawk 1, American Coot 40, Ring-billed Gull 250, Forster’s Tern 6, White-winged Dove 20, Belted Kingfisher 1, Red-bellied Woodpecker 3, Downy Woodpecker 6, Blue Jay 8, American Crow 25, Carolina Chickadee 15, Carolina Wren 2, Ruby-crowned Kinglet 3, Eastern Bluebird 5, Northern Mockingbird 2, Common Starling 60, Cedar Waxwing 60, Yellow-rumped Warbler 20, Northern Cardinal 1, Song Sparrow 16, Brown Cowbird 15, Common Grackle 60, Great-tailed Grackle 150, Red-shouldered Blackbird 12, American Goldfinch 12, House Sparrow 5.