Hooray for Nighthawk Nerds!


Me and the Canadian nighthawk researchers, Source: Anne Brigham

I wanted to feature this great interview by fellow nighthawk researcher, Gabriel Foley.

He’s part of our informal nighthawk research group which they call the Conflab, but I say it should be called the CONIflab.


Infrared Technology and Nests

Taken with iPhone8,4,iOS 10.3.2

Common Nighthawk rooftop nesting site.  The red is is the rubberized roofing material used as a substrate under the gravel. Here the gravel is in greens and blues surround the rubberized material. The eggs are the green ovals of the edge of the red patch in the upper right corner.

Last week, I used an infrared photo of a rooftop nighthawk nest to illustrate the importance of climate change research.

I tried to use this technology to find eggs and chicks, but as you can see above, there is no unique heat signature for eggs that I can use.  Nighthawks are extremely heat tolerant, and so their body temperature (and the eggs they incubate) match their surroundings pretty closely.  However, it’s been a great tool for visualizing this very phenomenon.

Other researchers like those in this great video on Marbled Murrelets, featuring my undergraduate research advisor Dr. Jim Rivers, use infrared to great effect in their nest searches.

Coming Out

Taken with iPhone8,4,iOS 10.3.2

Thermal image of rooftop nighthawk eggs (green ovals at the pointy end of the blue pencil) right after a female had left them.  Not too bad at 98 degrees Farenheit.

I’m coming out as a climate scientist.  There, I said it.

It seems absurd I have to say it, but that is the way of things these days.  I study a bird that’s extremely heat tolerant, but even they have their limits.  The mean maximum operative temperature (i.e. temperature experienced by the organism which incorporates wind effects) for Common Nighthawks  in my study 2014-2016 was 132.8 degrees Fahrenheit. I can’t really avoid the topic.

So, I have to look at the trends in temperatures, wind, cloud cover, and rain over time for my region and decide at what threshold these extremely heat tolerant birds can no longer survive.

The prognosis?  Mean temperatures in the Great Plains are expected to increase by 3.6°C to 6.1°C over the next 100 years (Preparing for a changing climate: the potential consequences of climate variability and change: central Great Plains. Colorado State University, 2002). For an excellent graphic that illustrates the temperature trends by global regions, check this out.



Sites where CONI satellite transmitters were deployed. Source: Elly Knight, WildResearch

Phew! Try to say that 10 times in a row! Common Nighthawks are given the CONI abbreviation in the American Ornithological Society bird checklists.  Put that together with the concept of migratory connectivity and voila! You get CONIctivity!

Ahem.  So, one question for many neotropic migrant (birds that migrant from the New World tropics) researchers: What is happening to these birds the rest of the year?  For Common Nighthawks, this is important.  In a previous post, I detailed the 9-month process that is the migration of these species.  The Cornell Lab of Ornithology site, eBird, has done a very good job of tracking migration by species based upon birders’ data.

However, if we want real time data, by the bird from a specific region, that will require satellite transmitters, which I detailed in a previous post. The great thing about this technological development is that we are not required to recapture these birds to download data.  Nighthawks are very difficult to capture.  They do not passively fly through nets when going from point a to b, their vision is extremely advanced, they are mostly active at dusk and dawn, and they tend to fly high unless they are actively defending a territory.

So, a team of researchers across North America (see picture above) set out this summer to attach transmitters at a number of locations and luckily we had a few tricks up our sleeves to catch these wily birds.

For this study, we hope to answer some needling nighthawk questions.  In particular, in some of these regions where they breed, nighthawks are increasing in numbers, and at others they are decreasing.  Is this a function of where they breed or their migration path?  We’ll find out in the coming year if the birds follow much the same path and timing, and where they stop and turn around.

An Unusual Field Season


Lady Sisyphus and a male who might be trying to persuade her to abandon her eggs and start a new clutch with him. She is not having it.


For nighthawks this was an unusual season.  This year, only 14 of last year’s 22 breeding females returned to their rooftop.  They could be at other rooftops, they might have died during the migration season, or they might be skipping the nesting season and just hanging around. This is my last field season in South Dakota, so I will never know.

Nighthawks returned 2-3 weeks later than last year, possibly due to the May Gulf of Mexico storms (that also wiped out some early nests on the Gulf).

On the flip side, June was a very mild month.  So many of the chick and egg die-offs associated with high-wind thunderstorms and heat waves didn’t happen for the first brood this year.

And one lucky bird, whom I have named Lady Sisyphus (pictured above), finally hatched an egg, the first in five attempts.  The chick died, sadly, but hey, that’s progress.

Eclipses and Birds


What do birds do during an eclipse?  Much depends on the day cycle of the species.  Is its diurnal, nocturnal or crepuscular?

As usual, Cornell Lab of Ornithology put out a great post on this subject.


  • Diurnal aerial insectivores like Purple Martins dropped from the sky and roosted.
  • Chimney Swifts that start circling their roost site at dusk began to do so.
  • Crepuscular nighthawks were active.
  • Nocturnal migrants dispersed.

More locally here in South Dakota, Dr. KC Jensen, of SDSU, reported the dawn chorus of many birds.

The Mythos of Nighthawks



There's this thing that nighthawk researchers encounter.  People don't know what a nighthawk is. Confusion about nightjar naming conventions is nothing new.

In fact, nightjars are often called goat suckers, presumably because people feared they were feeding from their livestock at night.  The irony is that nightjars are insectivores and were likely feeding from the insects attracted to their goats, providing an ecosystem service.

Sometimes it's because they have another name for this bird.  Here's an anecdote from a fellow researcher:

"I once ran into an old moonshiner while netting bats in West Virginia, and he told me this long story about the bullbats coming through in huge flocks in fall. It took me about 15 minutes to figure out what the heck he was talking about (in fairness, probably most of that was due to his West Virginia moonshiner accent). He was adamant they were really bats." – JB

Bullbats, in case you didn't know, are another name for nighthawks.  They have many names. Here's a list, courtesy of Idaho Fish and Game:

Common Nighthawk

Asseri Nighthawk


Cherrie's Nighthawk

Florida Nighthawk

Howell's Nighthawk

Mosquito Hawk



Pacific Nighthawk

Sennett's Nighthawk

Will O The Wisp

Booming Nighthawk


Burnt-land Bird

Eastern Nighthawk

Long-winged Goatsucker

Moth Hunter




Western Nighthawk


Pork-and-beans struck some of us researchers as particularly funny. That's what background actors say when they have to mouth words but not say anything whilst looking busy. Goes along with the ubiquity of nighthawks, once upon a time, I think. Another researcher noted that could be a bastardization of the nighthawk calls,

peent and boom


Finally, there's this account that came up in my nighthawk Google alert.  I'm always looking for others' research, but occasionally I get a fascinating bit of folklore:

"The Rolling Rock story of the Blackfoot explains why the Common Nighthawk (

Chordeiles minor

), referred to in the story as a bullbat, has such a small beak and sizeable mouth. It is said that Napi was cold so he borrowed a robe from a large rock but would not return it.  The rock got angry and began to chase Napi, so he called the nighthawks for help.  After the birds destroyed the rock that was rolling in his pursuit, Napi rewarded the nighthawks by pulling their mouths wide and pinching off their beaks so that they were "pretty and queer looking" (Grinnell 1913: 166-167). In another version of the story, Old Man asked the nighthawks for help, but subsequently changed his mind and accused the birds of spoiling his fun by destroying the rolling rock.  He punished them by tearing off their bills and splitting their mouths open wide, accounting for their appearance today (Wissler and Duvall 1908: 24-25). The nighthawks later retaliated by defecating on Old Man as they flew over his head.  Today, Blackfoot elders ascribe great significance to archaeological sites where Common Nighthawks nest."


The Winged: An Upper Missouri River Ethno-ornithology

 (K Chandler, WF Murray, MN Zedeño, R James… – 2017)


Perseverance Nevertheless

As I mentioned in an earlier post, Nature Conservancy has been highlighting the good news in conservation.  Nevertheless, there is so much to worry about these days.

Earlier this year, President Trump ordered a gag order for Department of Interior and Environmental Protection Agency employees, and the result was remarkable. Fearing that public information about contaminants and climate change would be removed from their web sites, EPA began migrating their data to  outside web sites that archivists and coders created. National Park Service employees moved their outreach efforts on climate change to rogue Twitter pages. Thus, like with Elizabeth Warren, persistence can happen, nevertheless.