The language of Sandhill Cranes

I visited Bosque del Apache wildlife refuge in early December, 2015.  I had visited a couple of years ago, but was unsuccessful in getting many decent recordings (see Bosque del Apache).  This time my goal was to get some recordings of the tens of thousands of Sandhill Cranes and Snow Geese that winter at the refuge.

Recording at the Bosque is difficult.  It’s right next to a busy Interstate 25 and a train track.  It’s also popular with birders and photographers, so there can be crowds to deal with, and its very hard to get a crowd to stay quiet when you want them too.

I arrived late on a Monday afternoon, checked into a motel in Socorro, then headed, not to the Bosque, but north to Bernardo Wildlife Management Area.  I had heard that there were fewer crowds there, so I might be able to avoid some of the “tires on gravel” sounds.  As soon as I entered the area, I found lots of cranes, some feeding, some taking wing back to their nighttime roosting wetlands.  There were a few other people (mostly photographers) around, but way fewer than are normally at the Bosque.  So, satisfied that this area had potential for some early morning recording, I headed back to the motel to get my gear ready for a pre-dawn trip.

When I arrived at the WMA entrance the following morning, I found a locked gate.  This turned out to be a blessing.  I took the road back toward the freeway exit, and instead of getting back on the freeway and heading south to the Bosque, I headed east to the Rio Grande river.   In the faint light of the fading night, I caught a glimmer of water just south of the road and pulled over to find a wetland full of cranes.  I quickly set up my parabolic dish pointed toward the wetlands, and watched the cranes lift off right over my head, against a backdrop of a stunning sunrise.

First in small family groups, then in larger and larger groups, they lifted off in a cacophony of flight calls, some flying right over the mics on their way to feeding grounds up north.  It was amazing and beautiful and I was thrilled to be able to record it.  Of course, there was the occasional vehicle on the highway I was parked next to, gun shots from upstream (apparently it was hunting season) and the drone of the semi-trucks on I-25, but the stunning sights and sounds overwhelmed everything else, including the icy 22F temperatures that morning.

The cranes flew close enough overhead that I could hear their wing beats.  I was struck by the variation in their flight calls – that deep, chesty squawk that can be heard from more than a mile away.  The calls differ between males and females (males being lower in frequency) and by age.  The plaintive whistles of the juvenile cranes were obvious, as they struggled to maintain contact with their parents.

I recorded and watched in wonder for more than an hour.  By that time most of the cranes had already flown over, so I packed up my recording gear, warmed up the car and headed back to Bernardo.  The fields were full of cranes and some snow geese, with quite a few photographers already lined up with their gigantic telephoto lenses.   Some of the cranes in the fields danced and cavorted, perhaps warming themselves up or perhaps preparing for the breeding season in the upcoming months.

Sandhill Cranes use at least 20 different vocalizations, including soft purring sounds for maintaining contact among family groups, loud squawking flight calls for coordinating groups in flight and on the ground, and trumpeting alarm and unison calls (and many variations of each type).  Cranes also communicate with a variety of postures, both subtle and dramatic.  The most dramatic of these is the mating dance – a coordinated set of moves by males and females that involves deep bows and jumping into the air with wings spread, while vocalizing a lot.  The amount of vocalizing and posturing by cranes makes them very fun to watch.

After spending some time at Bernardo, I headed to Bosque del Apache.  At the south end of the tour loop, there was a mixed flock of Sandhills, Snow Geese, and Canada Geese foraging in a field.  I set up the parabolic mic again, and was able to record some of the other crane vocalizations, including the purring contact call, and the loud attention call, in addition to calls of some of the geese:

The Snow Geese are a big attraction at the Bosque, and you can almost guarantee wherever you find snow geese you will find a large flock of photographers.  I’ve heard from several sources that the sound of several thousand Snow Geese taking wing is remarkable, and something I wanted to record.

But getting away from the crowd was a challenge.  Recording them from the flight deck at the Bosque was out of the question due to the crowds, but I managed to get a few minutes of recording of a large group headed back to their evening roost.  The next morning, instead of going to the flight deck with the crowd, I planted myself at an observation deck at the north end of the tour loop.  The geese cooperated nicely, flying  overhead by the thousands on their way to their feeding areas.

I combined a couple of recordings to try to give the impression of the take-off and overflight.

Bosque del Apache, and nearby wildlife management areas, are such a treat for the senses.  The beautiful reds and golds of the vegetation, highlighted by the low winter light, plus the tremendous amount of wildlife, make the cold temperatures worth it.  I also was very fortunate to have good recording conditions – no wind or rain.  I hope to get back in the spring, to see what it looks and sounds like then.

For more Sandhill Crane recordings, see The primeval grace of Sandhill Cranes.

References:

Nesbitt, S.A. and R.A. Bradley. 1997.  Vocalizations of Sandhill Cranes.  North American Crane Workshop Proceedings, paper 227.

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