Guerrero, Mexico: Gulling and Montane Birding

Although I was still based in Ixtapa, I rented a vehicle so I could visit the northern edge of the Sierra Madre del Sul. The area closest to Ixtapa is not remotely as good as the fabled Sierra de Atoyac a few hours to the south, where the endemic Short-crested Coquette is found. However, as I had pioneered birding the highway through here, I wanted to continue discovering which bird species were present. Highway 134, which crosses the northern edge of the Sierra, can be periodically unsafe due to banditry. Fortunately, Will’s wife has relatives who live close to the pass and he was kind enough to check with them and confirm it was currently fine.

In addition to birding the mountains, I had been spending a lot of time checking satellite imaging of the coastal plain to look for potentially good wetlands. When I checked the images of the mouth of the Atoyac (formerly Balsas) River, on the border with state of Michoacan, I noticed that there was clearly a power station outflow into the ocean just east of the river mouth. Being familiar the Dungeness ‘patch’ – the outflow from a nuclear power station that is noted for attracting large numbers of gulls and terns – from my UK days, I immediately conjured up images of hundreds of terns and Laughing Gulls replete with multiple rare gulls. I simply had to visit!

Note to readers. This post is very light on photos as I was birding on my own. Much of the time in the mountains, I was struggling to even see birds and didn’t bother with my camera. This came back to bite me a bit at one spot where I had both Red-headed Tanager and White-tailed Hummingbird posing nicely.

Since I wanted to bird much further down the interior slope than I had previously, I got up at 3.30 AM and arrived at my target location just prior to dawn. Since I had previously seen interior species like Black-chested Sparrow and Dusky Hummingbird much closer to the pass, I was expecting to have a chance at birds like Gray-breasted Woodpecker and Pileated Flycatcher. However, when I arrived at the location, the habitat was lusher than I expected and few birds I did see, like Orange-breasted Bunting and Golden-cheeked Woodpecker also occur commonly on the coast. I suspect that the lower elevation of the mountain ridge here has a lesser rain-shadow than the much higher Atoyac area.

After an hour of birding, I cut my losses and headed back towards the pass. A couple of stops is some arroyos about 10 KM before the summit proved productive with Dusky, Ruby-throated and Violet-crowned Hummingbirds, Golden-crowned Emerald, Black-chested Sparrow, Mexican Squirrel Cuckoo, various warblers, Hooded, Bullock’s and Streak-backed Orioles and both Indigo and Varied Buntings. At the pass itself, a stop in the pine-oak added Painted Redstart and various migrant warblers, Rufous and Berylline (many) Hummingbirds and a Hammond’s Flycatcher.

Feeling a bit more upbeat, I now started to work the coastal slope of the pass. Further efforts to find hummingbirds in a flowery section proved frustrating, although I did find a female White-tailed Hummingbird here. This Guerrero near endemic is regular up in the area. As I worked my way down the road, bird activity proved to be virtually zero. It was already midday and, although not particularly hot at this altitude, very little was calling. I also found that mobbing and scolding playback was completely ineffective. Over the course of this day and the next, I concluded that the very steep mountain slope was probably a deterrent to birds coming in, as they would have to exert energy flying up the steep slope or flying back up if they dropped down from where they were. Since mobbing is more of a ‘leisure activity’ when they don’t have young to protect, they couldn’t be bothered to expend a bunch of effort to get to the locus of the activity.

Operating on that theory, I went down to the lower edge of the tropical evergreen section where I knew a gully provided a greater concentration of trees on less steep slopes. Here the mobbing playback did pull in a few birds. Very fortunately, one of these was a female Violet Sabrewing – a Guerrero tick – and a bird that made the long drive up and down the mountains seem more worthwhile.

Since it was now past 1 PM and almost a two-hour drive to the power station outflow, I got moving. Arriving in Petacalco, I cruised down the main street until I found a pollo asado place and grabbed half a grilled chicken and some onions before heading out to the outflow. There were dozens of Snowy Egrets feeding there but NO gulls or terns – ouch! Since I couldn’t see very much of the beach to the west of the outflow, I parked the car and walked down on to beach. I immediately saw a small tern with a ‘dipping’ feeding style – a Black Tern. Although these are common winterers offshore in Guerrero, I had yet to see one as I have never been far enough offshore. It now became apparent that there were terns and gulls feeding off the beach. Scanning west, I could see a couple of flocks on the beach near the mouth of a small creek. There was a rather pale larger-looking gull but it was too far to make out much on it. There was quite a bit of disturbance from other people walking along the beach and by the time I reached the creek mouth, there was no sign of any large gull. There were a couple of Ring-billed Gulls in with the Laughing Gulls and I concluded the bird must have been one of those. I moved a little forward to view an area where I suspected there were a few gulls out-of-sight below a little ‘sand cliff’ and was shocked when a first-winter Glaucous-winged Gull appeared! That was certainly not on my radar for the state. Since gulls are easy to photograph, I was carrying my camera and was soon able to get some good photos. I even managed an in-focus flight shot.

Glaucous-winged Gull

Further checking revealed four Ring-billed Gulls and over 80 Laughing Gulls – a good number for the coast here. So it does look like this location has some decent potential.

Driving back to Ixtapa, I took a minor diversion to check out access to the east shore of the Laguna del Negro. The Black-collared Hawk along the Playa Linda Bike track had been on the extreme SE end  of this laguna, but very little of the open water is visible from that location. I was able to find an area to view much of the laguna but there were none of the hoped ducks visible. I suspect this side might be much better come March/April when water levels have dropped significantly. I did have some compensation in the form of a roost of at least 150 Dickcissels.

The next morning, I headed back up to the Highway 134 pass. My plan was to begin at dawn in the section where I had seen the sabrewing the previous day, with the fairly safe assumption that activity would be better early in the day. I parked about half a kilometer above the sabrewing spot and very slowly worked my down.

There was clearly much more bird vocalization compared to the previous midday visit, when Brown-backed Solitaire was about the only species singing. Several solitaires were audible as soon as I got out of the car and I soon heard two different Collared Forest-Falcons sounding off as well as a Singing Quail. Although greatly improved, my knowledge of Mexican bird vocalizations is decidedly patchy and I decided to try using the Merlin app to see what else was around. Although it produced a couple of the usual howlers – Rufous-collared Sparrow and Rufous-browed Peppershrike – Merlin did alert me to the presence of Orange-billed Nightingale-Thrush, Red-crowned Ant-Tanager and Collared Trogon. I was able to verify that these were in fact calling and the ant-tanager proved to be quite common along that section of road. Merlin also detected Fan-tailed Warbler twice but I didn’t hear one or get one to respond to playback. I saw my first ever Fan-tailed Warbler her many years ago and the habitat looks very good. There were also a number of unknown vocalizations that neither I or Merlin could identify.

Although I was hearing some birds, I was still struggling to see anything or get much into playback or mobbing calls. I eventually made it down to the sabrewing spot and the mobbing tape finally worked its magic. A good number of the expected montane-wintering warblers appeared, including Tennessee and Black-throated Green Warblers, even though I could only get identifiable looks at a minority of the birds that came in. A pair of Flame-colored Tanagers and a Masked Tityra investigated from high-up in a tree, while a Ladder-backed Woodpecker came close. This species seems quite regular along this road section, even though the habit is rather lush in most spots. At that point, a woodcreeper landed on a nearby trunk and began calling loudly. The bill was clearly too slender for an Ivory-billed but the call seemed wrong for a Streak-headed, which I had been using playback for earlier in the morning. I decided to try Merlin on it and was surprised when it immediately came up with Spot-crowned Woodcreeper, a species that I had seen previously at much higher elevation in the cloud forest about Atoyac. This time Merlin was clearly correct and I was able to see well the spots, not streaks, on the head and the lack of streaking on the mantle. A few birds were also down in the lower vegetation next to me and I finally got a decent visual on a pair of ant-tanagers as well as a Golden Vireo and Golden-crowned Warbler. An Ivory-billed Woodcreeper also popped up nearby, but a Collared Trogon called invisibly.

I then worked my way back up towards the car. As I was watching a small flock, which contained a Slate-throated Redstart, I became aware there was a fruiting tree by the road. Watching this for 15 minutes turned up nice looks at a pair of Collared Trogons, Gray-crowned Woodpecker, Brown-backed Solitaire and tanagers. I continued past the car as the road further up had some good overlooks with potential for swifts and raptors, although I have never had much luck with either here. After hearing several Green Jays, I finally got good looks at one by the roadside.

Fairly satisfied with the first few hours, I then headed up towards the pass area to where the pine-oak habitat began. Similar to the previous day, the mobbing tape worked much better here. The same gang of Berylline Hummingbirds appeared in a feisty swarm, joined by a male White-tailed Hummingbird that perched at close range. Four species of tanager were headlined by three Red-headed showing amazingly well. Two Black-headed Siskins and a Rusty-crowned Ground-Sparrow showed well but briefly. I then walked back from the pass a half kilometer or so towards the coast, where there are many flowers by roadside. I just saw a few more birds of species I had seen earlier in day with one exciting heard-only exception – a pair of calling Military Macaws.

With bird activity dying down, I decided to head back down to my next hotel in Zihuatanejo, where I would return the rental car. I made a 30-minute stop along a stream to photograph damselflies as the list of odonata recorded in the state is pathetically low. Some years ago, I photographed three common odes at the pond in El Refugio de Potosi and they all transpired to be first state records. We will see how these more recent photos go.