Saturday, March 31, 2012

Have You Seen BirdCast?

At first I started using eBird because I liked the idea of my everyday sightings being useful for science.  I quickly grew to love how simply it organized all my sightings and lists.  Eventually, I learned how to use the data myself, by looking at bar charts and maps.  More recently, I've been amazed by the animated occurrence maps made from eBird data.

Now the folks at eBird have teamed up with NOAA and others to create BirdCast.  Using predicted weather patterns along with records of past weather patterns and eBird data from past years, Cornell is now posting a weekly report of predicted migration patterns, as well as a followup summarizing what actually occurred.

Check out this week's BirdCast report.  Reading over the section for the West, I learned to keep an eye out for the first Vaux's Swifts this week.  Also, the Lawrence's Goldfinches we have been seeing in recent weeks may begin to head west toward the core of their breeding range; hopefully, some of them will stick around to breed here!

Saturday, March 17, 2012

A Spectacle of Swallows

The field season has kicked off once again, and I spent the past ten days with the 2012 Great Basin Bird Observatory (GBBO) crew around Blythe and Yuma (Cibola and Imperial NWRs).  The beginning of the field season is the most difficult work, clearing trails and scouting plots to ensure that surveys go smoothly.

Resting on a small trail my crewmate and I carved through an arrowweed stand (Photo by Brandon Breen)

During this first tour, the crew spent several nights camping at Fishers Landing on Martinez Lake.  The campground itself was nothing to write home about, but the birding in the area was pretty good.  One thing we noticed at our campsite was that streams of hundreds of Tree Swallows would pass overhead each evening.  This was no surprise to any of us who had spent a spring along the Colorado River before, as migrating streams of swallows are a common sight out here.  One evening, though, we went up to an overlook point to scan the lake and we were impressed by the number of swallows streaming over the water, swirling over the marsh, and gathering in flocks high over the lake.  Eventually, all the swallows gained elevation and streamed into the masses high in the sky.  Numbers increased rapidly, from a few thousand to more than 20,000 as we stood and watched, estimating numbers repeatedly.  The ball of swallows moved through the sky with the liquidity of smoke, merging and splitting, climbing and shifting as the light dimmed.  Eventually, a few hundred birds broke off from the flock, diving almost straight down toward the marsh before breaking at the last moment and settling into the cattails, preparing to roost for the night.  As more and more birds joined in the plummet to the marsh, they appeared as whirling vortices to the naked eye, like twisting pillars of smoke.  Soon the clouds of swallows had drained to nothing, and as darkness fell, and two Black Rails began calling from the marsh, we headed back to the campsite.

The next night, having heard from us the spectacle we'd seen, most of the crew took the walk to the viewpoint.  The swallows were out again, streaming over the water and building in flocks over the marsh.  Eventually the flock built to an estimated 50,000 birds, more than twice the size of the previous evening's flock, and twice as spectacular!

The swallows' marsh
The crew enjoying the swallows (Both photos above by Brandon Breen)
Watching the swallows spiraling down to roost

I've seen some fantastic migration events, with the raptor migration of Veracruz topping the list: a constant stream of Broad-winged Hawks, Swainson's Hawks, Turkey Vultures and others topping 250,000 in one day!  At Hazel Bazemore near Corpus Christi, TX, I've seen kettles over 10 and 20 thousand.  This sight of swallows gathering at dusk was equally spectacular to me as those kettles of hawks.  It occurred to me while I watched this that this surpassed any gathering of cranes in Arizona or New Mexico.  Why not have a March Swallow Festival?  After all, our count of 50,000 wasn't even very high--last year's high count was about one million, and that wasn't unprecedented.  In early March last year, I counted nearly 3,200 Violet-green Swallows migrating over Rotary Park in an hour and a half.  This is a regular phenomenon in this area--even researchers are beginning to look at it using radar.  I would like to see a time in the near future when wildlife enthusiasts from all over the country (the world?) come to the Lower Colorado River Valley to see the swallow migration!

Thursday, March 15, 2012

Nutting's Flycatcher

By now, the Bill Williams Nutting's Flycatcher is anything but news.  In the first week or two after its discovery, it was fun to see the bird mentioned in blog posts, Facebook feeds, and websites.  Now, more than five weeks later, I still enjoy being out there with people seeing it for the first time, and generally hearing from visitors.  One of my favorite stories that I've heard of the bird was from Joe Kahl, a biologist on the Lower Colorado River.  He was checking in to a hotel in Lake Havasu City, staying the night for some local bat research.  He only heard about the Nutting's when a clerk at the hotel asked him, "Are you here for the rare bird?"  It's a great thing for birders to be able to see a new species, but even better when locals learn that said bird brings in tourist dollars!  More recently, the Nutting's has even been featured in the local newspaper.

 The Discovery

The discovery of this bird took a lot of luck.  Since I was working on my Mohave County Big Year, David and I decided to do a day hike in the Bill Williams River riparian area on December 18.  We entered at what field biologists call the Cross-River Trail, which is the only point in the riparian where you enter Mohave County almost immediately (usually it takes at least a half-hour trek).  Soon after entering the forest, we found ourselves among a mixed flock of birds.  David started pishing, and then we heard this weird call.  We puzzled over it for a few minutes, eventually agreeing that it sounded like a Myiarchus flycatcher.  The only Myiarchus around, though, is Ash-throated Flycatcher, and this didn't sound like one.  We puzzled some more, until David finally said what we were both thinking: "Maybe it's a Nutting's."  I should add here that Nutting's Flycatcher is always on our minds when we enter the Bill Williams riparian area, after one was recorded there in fall of 2008.

I got out my iPhone and flipped through every bird sound on it, but there was no Nutting's Flycatcher.  We tried to find the bird, but it was invisible among the cottonwoods.  Eventually it moved away from the trail, and we were left to wonder.  We continued our hike, four hours of winding through the trail system on the river.  As we arrived back at the road further west of our entry point, the mystery call came up again.  Nutting's Flycatcher seemed like the best possibility.  We went back to where we had heard the bird, and we did hear a single, distant call, but couldn't get through the dense mesquite to where it had called from.

So it was back home for the day, and straight to xeno-canto.  It took some digging through all the songs of Nutting's Flycatcher, but eventually I came across a recording of the single, long "wheep!"  I turned to David and said, "That was it.  It was a Nutting's."  Just to be sure, I went through the pages for other species, and Great Crested Flycatcher gave me pause.  A similar call, similar quality, but it seemed disyllabic, whereas the Bill Williams bird gave a call that was rising, but distinctly monosyllabic.  Clearly, though, we needed to be there the next day, better prepared for what was out there.

Armed with recordings, we arrived the next morning (December 19) to find a silent forest.  It took about an hour of wandering and listening before David's sharp ears picked up a "wheep".  We hurried toward the source of the call, playing "wheep"s back at it and confirming that they sounded identical.  We began to get frustrated, though, when the bird didn't come in to the recordings.  It was only after David and I split up, and I crouched in a thick stand of black tamarisk trunks and played the song, that I heard a short, burry response, and the bird popped up in front of me.  It was a glorious thing!  Right there at eye level, with a tiny bill and lemon-yellow belly, it struck me how much it looked like a Dusky-capped Flycatcher.  After a moment, it flew over my head and flew toward the stream bank behind me.  The significance of this hit me quickly.  We understood that stream bank to be the county line, so it was possible that the bird had just flown from La Paz into Mohave County.  I hurried back to the stream bank and waited with David, and after a few seconds the bird popped up in the brush on the La Paz side, giving short, burry "wheep" calls in response to the tape.  I felt my heart skip a beat as the bird took wing, crossing over our heads and into a willow just on the Mohave side of the stream bank.  Now we had ample time to study the bird, to take photos and recordings, and to marvel at how this Mexican species could turn up on this river again.

We eventually dragged ourselves away from the bird to get the word out.  We ran into Refuge volunteers Bobby and Wayne Paintner on our way to the Headquarters, and told them of the bird.  We made excited phone calls from a rare point of cell reception at the Headquarters, then visited Refuge Ecologist Kathleen Blair to tell her all about it.  Over the next few days, we went out several times with friends to see the bird.  At first there were surprisingly few visitors.  Then calls and emails started coming in, and positive reports continued while David and I were in California from late December into early January.  Planet Ranch Road has now seen hundreds of visitors, and I still find birders there every time I visit.  The Nutting's was even the last new species seen by John Vanderpoel in his recent Big Year.  A near-constant stream of friends has been coming to see the bird as well.  As much as I enjoy seeing and finding rare birds, it is a whole other dimension of birding to be able to share something exciting with fellow birders.