What an amazing encounter Eric! You might consider taking a video of this behavior if you see it again!
Jan Gorski Highlands Ranch, Douglas, CO On Thursday, June 27, 2019 at 8:14:08 AM UTC-6, Eric DeFonso wrote: > > Hi all, > > Indulge me if you will, I want to share a very lengthy but hopefully > entertaining account of what for me was an unusual and astonishing > experience with a common species...or at least one that many COBirders have > been lamenting this year as not being as common as usual. > > I was setting up to camp at Smith Reservoir SWA in Costilla County, near > Fort Garland. Around 7pm I was on the SE corner of the reservoir with > magnificent early evening light behind me illuminating the place, when I > spotted a Common Nighthawk (CONI) bounding in the northerly breezes over > the water. It's always a delight to catch sight of a CONI flying relatively > low and close, allowing for nice looks in the scope, especially in that > nice light. > > A few moments later, I noticed a second CONI flying near it, also doing > the same bounding flight in the breeze. I watched them both carefully, and > thought for a moment that I should check to see if by chance one of them > might be a Lesser Nighthawk (LENI). Neither fit that description, but I > kept checking anyway just to be sure. My one Colorado LENI was seen with > the delightful pair of Coen and Brenda over in Nucla a few years ago, also > coursing over water with a bunch of CONIs, so it seemed proper to be alert > to it here too. > > I scanned the rest of the reservoir as well, looking for ducks, herons, > and any other waterbirds that might be of interest. I've not spent much > time over the years in Costilla County (and apparently not all that many > other Colorado birders either, judging from eBird), so county lifers were > fairly easy to come by that day. I went back to check on my nighthawks, and > now there were 4. I mean 5! Cool. All of them doing the same thing, > bounding in the breeze, and working their way towards the middle of the > reservoir. I noticed at that point that they'd get to about the middle of > the water, and then let the strong breeze blow them all the way back to the > south shore, at which point they'd start the process again of working their > way to the middle. It was a kind of "conveyor belt" of CONIs, as they > hoovered up low-flying insects over the water in their version of a feeding > frenzy. Again, I kept checking to see if any of them were LENIs, and none > of them fit the bill, but my attention was drawn in now and I kept checking > each bird anyway every minute or two, because "you never know". > > After several more minutes, I counted the CONIs once more and now there > were 10! Wow, that's cool, I'm not used to seeing all that many in one > place at one time. Oh sure, maybe when they've just arrived after migration > and they are accrued in a few concentrated spots, but I hadn't seen that > myself in quite some time, so it was again neat to see. And all of them > again engaging in the same "conveyor belt of CONIs", providing a bit of a > scanning challenge when they peeled off to start over but also providing a > chance for steady viewing if you followed one in the scope as it slowly > coursed its way to the middle of the reservoir. > > After another several minutes, I counted 16! Wow, now I was getting close > to seeing as > many as I've ever seen at one place and time. Still checked for LENIs as > best I could, but all of them sported very pointed wings. I should mention > that the scene was pretty quiet except for the sound of the steady breeze > blowing. It was cool to watch all this bird activity occurring in silence. > The Eared and Western Grebes seemed curious to see this growing number of > CONIs flying over them and foraging so differently from their preferred > subaquatic style. > > Around 7:30ish it seemed like there were more than 16, so I carefully > counted again and now there were 40! Holy cow, that's definitely way more > than I've ever seen at once. I figured that seeing that many at once may be > typical of a migration flight. but that's something I'd not personally > witnessed, so this began to feel like an extraordinary occasion. I thought > back to those COBirds posts about the disappearance of CONIs from various > local spots in the Front Range, and thought, well, no shortage here at > least. I should mention that the surrounding terrain is largely > sage/rabbitbrush shrubland and ag areas. > > It was quite a challenge at this point to keep track of any individual > bird even in the scope. There was no shortage of choices of birds to watch > of course, but like trying to watch a single swallow among a cloud in > binoculars, a single CONI in the scope proved elusive simply because of all > the other choices that were moving about in the scope's field of view. A > happy problem to have of course, but it didn't make the search for a > possible LENI any easier. > > Some minutes later, I thought to count once again. By the way, my method > of counting such a dynamic, shifting bunch of birds was to start at the > southern end of the water and slowly scan in the bins northward as the > birds were slowly making their way there. That way I thought I'd reduce the > chance of double-counting since I could count the birds I was scanning past > easily (they were flying slow, into the wind), and then count the ones > zipping by quickly on their way back to the beginning of the conveyer belt, > knowing that I hadn't counted them yet. It was still a rough count because > so much is happening pretty quickly but I felt confident in my end result > to within +/- 10%. Now I was certain there were at least *93* nighthawks on > the reservoir! > > Looking with the naked eye, it was clear there were dozens and dozens and > dozens of them. Again, all bounding silently in the breeze above the water, > but presumably ravaging the insect life in the process with calm, cool > efficiency. I definitely had never seen that many CONIs at once. I started > to wonder, when does this end? How many birds are going to show up here?? > Will anyone believe me? > > By 8ish the light was starting to lessen. It was still nice with sunlight > streaming over the water, but not as bright as it was an hour earlier. I > was still scanning for LENI, but at this point it didn't really matter > because it was so amazing to see that many CONIs engaging in this > gregarious feeding event, all low over the water and all in easy viewing. I > thought for a moment that I really wasn't going to be able to do counts any > more, since it was tiring and getting tougher. But I didn't want the late > hour (I needed to get to sleep soon for a very early start the next morning > with a bird survey) to keep me from knowing *just how many CONIs can fit > above a reservoir*, and I also right then began to envision how I might > share this remarkable event with the COBirds listserv. > > The next count yielded 160 CONIs! At this point I was starting to count by > 10s, as quickly as I could before the mass of birds rearranged themselves > significantly over the water thus making counts fraught with potential > double-counting errors. Again, I didn't doubt my result since it was a > veritable cloud of CONIs. The scope field of view at any one time had no > fewer than 10-12. I had to be careful too about not counting swallows, > because at this point they were getting in on the hoovering conveyor belt > action, and in the diminishing light it was getting easier to conflate the > numbers of nighthawks and swallows. But even allowing for some amount of > counting error, it was clear that there were ever-increasing numbers of > CONIs present. > > I wondered, "Where are they all coming from??" I looked at the south and > west edges of the reservoir and noticed that one or two at a time were > regularly joining the scrum from the bordering shrublands. It was as if the > CONI call-to-action had been sounded and they collectively were fully aware > of what a bonanza Smith Reservoir could be. > > Quarter past 8 and the light was fading. The sun had set but I could still > resolve individual birds coursing about. Time for one last count before I > surrender. *210* this time! So many CONIs, it was truly a spectacle. I wish > I could have photographed it somehow, but how do you capture that many > birds in this circumstance in a way that people will believe your big fish > story? And the birds themselves... how could there be enough for them all > to eat in this one spot? Where did all these birds roost? How far had some > of them come? Was it like this over all the large SLV bodies of water? Is > it like this over other large reservoirs in Colorado, and I'd just never > noticed? I have lots of questions, and haven't really had time to look up > answers. > > The eBird quantity filter tripped at around 100 birds, so at the moment my > checklist for the evening doesn't show on the public results, and won't > unless it gets confirmed. But for those curious, this is the link to my > submitted checklist: > > https://ebird.org/view/checklist/S57661005 > > I don't know if the CONI frenzy continues every night there, but I will be > heading back to that area in mid-July for another survey and I plan to camp > there again. I would love to hear any stories or accounts of dozens or > hundreds of CONIs observed in one place and time, especially over > reservoirs. Birds of North America Online says the following about CONI > foraging: > > "May forage in large groups at local areas. A flock of about 110 > individuals observed foraging in an urban area west of Toronto, ON, in a > 1-km2 area; individuals spaced about 20 m apart (Ewins 1993a > <https://birdsna.org/Species-Account/bna/species/comnig/references#REF42078>) > and similarly near Regina, SK near dawn in spring (RMB unpub. data). Flocks > of 1000's reported in Kansas (Cummings et al. 2003). At Okanagan Falls, BC, > 50–300 birds foraged over a 100 m stretch of a river every night (Brigham > and Fenton 1991 > <https://birdsna.org/Species-Account/bna/species/comnig/references#REF42072> > , Brigham and Barclay 1995 > <https://birdsna.org/Species-Account/bna/species/comnig/references#REF32847> > )." > > For those discouraged about low numbers of nighthawks in their areas of > residence compared to past years, at least be heartened by the fact that at > least in the SLV, hundreds of them are gathered and making a good living > there this year. > > Thanks for reading this far! > Eric > > ----- > Eric DeFonso > near Lyons, Boulder County, CO > -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. 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