Black-chinned Hummingbird

Weight of this individual: 2.8 g
(average weight for a male = 3.09 g)

* I'm not sure if the average listed is a spring/summer weight or not.

This is one of the hardest things to deal with in rehab: knowing that you CAN help, but only so much. The lovely fellow above, adult male Black-chinned Hummingbird, died of emaciation/starvation/drought. Matt found him in the yard, unable to hover more than an inch off the ground. By the time I got outside, he was on his back. Once in hand, his beak was placed in a hummingbird feeder and he managed to get a few good strong slurps. Placed in a sheltered spot with a perch and nectar source, I thought he was dead in the morning - his head rolled back when I picked him up and he was limp. There was a buzz in the chest and he responded with beak movements when his bill was nudged into the nectar. A few sips and some gaping and the buzz in his chest accelerated before stopping. Eyes closed.

Ethically, the decision to interfere with nature would be an interesting discussion. However, in the grand scheme of impacts on birds, nature barely has any say - many young birds still die of natural causes (too many mouths in the nest) but for adult birds, the death toll by unnatural causes is ridiculous. Windows do not single out and kill the sick or the injured. Wind turbines do not single out and kill the sick or the injured. Cars often enough do not single out and kill the sick or the injured. Power lines do not single out and kill the sick or the injured.

So in my book, any bird that CAN be helped SHOULD be helped. And any bird that can't? That's what salvage permits are for.

Nighthawk, none-the-Lesser

Chordeiles acutipennis
Lesser Nighthawk
Forever sleep.
Roadkill.

*Recall that we are permitted through Texas A&M University.

Amongst birders, there is oft the exchange of "is it lesser or common, is it lesser or common, is it .... ?"

Enough.

I generally hear that when outside the Lesser Nighthawk's range in much of TX. Where they may get a few here or there. Or do they?

In the trans-Pecos, we get both. Perhaps even more Lessers to an extent. It's not too difficult to tell them apart when you live amongst them.

"Nighthawks" are in Family: Caprimulgidae, along with "Nightjars." Generally having long pointed wings. Mostly active at night, they are sometimes seen in daylight, often come dusk.

Lesser Nighthawk


If you were to successfully pull this bird, perched on a branch of an old oak, out of the matrix (it happens) and were with a throng of birders you would again hear that many-voiced mumble-roar "Is it lesser or common, is it lesser or common, is it ..."

Look at those long primary wing feathers. Do they have small, buffy-tan spots on them?
Aye.

You are then looking at a Lesser Nighthawk.

Fanned out:



This particular bird is a male. The best way I can tell is that WHITE "primary wing-bar." The females' stay buffy-tan like those aforementoned Lesser Nighthawk wing-spots.

Underneath as well for the male:


Nighthawks are entirely insectivorous. Like many avian insectivores, they sport bristles at the base of their culmen:


Their tiny beaks do no justice in illustrating just how wide their mouths open. Those hinges are pretty far apart:

Heidi taught me in the past that wildlife rehabbers have real issues with feeding injured nighthawks and nightjars. Insects, yes. However, they only feed on the wing and these guys fly fairly rapidly. At their rate of speed to the prey-item, that flying insect is thus moving the nighthawk's way very quickly as well. They can't successfully feed by dropping a cricket down the hatch. Perhaps she can speak more on that.
This individual needed no rehabber.

Though nearly always observed on-the-wing by mere humans. They ofcourse have feet. They perch; also, they scratch and preen like Aves do. Check that "toe" :

Long-legged, they are not.




Lesser Nighthawk also fly far more consistanly close to the ground. (Which makes them a seemingly big roadkill hazard out here. They are extremely aerodynamic which is an asset. I can't believe I've yet to hit one. So many close-calls. I'm quite glad I haven't.)

Common Nighthawks give a classic well-known vocalization in flight. Lessers DO NOT vocalize in flight.

Common Nighthawks fly high and have a bouyant quality about them in flight, with fewer wingbeats. Longer-winged than the Lesser, that white primary bar also does not go as near to the wingtip with Common Nighthawk. Though the latter, hard to tell if that is the only of these qualities one looks for.

Finally, yet once again, whether perched as in the initial photo or in flight in good light with good looks... :



... those buffy-tan spots on the primary wing-feathers.

The Texas Cooperative Wildlife Collection (check link in sidebar) at Texas A&M University does not have a Lesser Nighthawk for Brewster Co.

Here you are, Dr. A.

Sweltering birds

On Tuesday (May 24) we trekked the Colima trek for the last time before the mountains get too hot for the summer; one Colima Warbler and a few dozen empids were our reward. Back in the Chisos Basin, we treated ourselves to lunch and saw one lonely Great Purple Hairstreak - it was our only butterfly for the day. Down at Panther Junction, at a private residence, we relished long looks at a very close Gray-cheeked Thrush (quite unexpected!) and some less-rare-but-equally-stunning passerines: Black-headed Grosbeak, MacGillivray's Warbler, Townsend's Warbler, etc.

As of Tuesday, we also ended up with a brand new nephew and the discovery that high fever in small dogs can cause seizures. It was an educational day all around.

Today, Saturday (May 28) it's 96 in the shade with a high of "only" 100 while the rest of the state is facing 105 on up. So it was strange to see another birder out in the midday sun; Byron Stone of Austin even kicked up a Sprague's Pipit at the motel pond. We relocated it twice, and saw a few more regional specialties for the day: Zone-tailed Hawk, Varied Bunting, MacGillivray's Warbler, etc.

Safe weekend, everyone!

Other updates

The Iron Mountain Fire seems to be an old memory; Marathon and Fort Davis and Alpine (and Marfa and Sanderson, for that matter) are all back in business with no road closures, no smoke and a burn ban that will cost you $500 if you don't have a permit for your welding, grilling, campfire, etc. Don't Even Think About It.

As for the Yellow-breasted Chat a few posts down:

"I am sorry to report that he did not make it. Very few cat caught birds ever do. I think it has to do with all the stress they go through, and they keep on fighting and their adrenalin stays up. Finally, at night they just give up. If they make it 48 hours, they usually survive. It is the first night that gets them. You cannot imagine how sick and tired I get of cat kills. ... I have seen hundreds, if not thousands over the past 23+ years." (from the wildlife rehabber)

the drying, the drought

"...this is one of the effects of an extended drought that most persons don't realize or notice directly." - Dr. Keith Arnold

There's still a Green-tailed Towhee and a White-crowned Sparrow on 'the back forty.' They should have left a long time ago. They have the energy to stay, but not to leave.*

Common Nighthawk - one - returned to town on May 19th. The evenings are silent and empty without them. Lesser Nighthawk - one - returned on April 17th. A few seem to be around. Where are the rest?

Bats had a good, strong, dense show early on. Since then, maybe one or two each evening. Perhaps that was migration.

Barn Swallows sit on the ground; they have no mud for nest building nor energy to do so. They wait for insects to come to them.

Western Wood-Pewees perch uncharacteristically low, barely above the ground.

Audubon's Yellow-rumped Warbler did not wake up this morning. Second, perhaps third adult bird I've ever knowingly picked up that died of natural causes. The keel, breast bone, photographed above, is a jarring reminder that fat stores = life. Lost muscle mass, emaciation, a beautiful bird with no life inside, that is the story of a severe drought. Native predators are coping. Unnatural predators are wreaking havoc.

Scott's Oriole (below) did not wake up this morning either. Third or fourth adult bird that I've ever knowingly picked up that died of natural causes.

It is fairly well known that birds lose a significant amount of weight overnight. The question of how much will definitely vary by species and a considerable range of external factors. I highly suggest reading up on this as a way of understanding what pressures birds face without ANY human/predator/artificial pressures.

This sort of widespread bird die-off is more common among insectivores who migrated too early and were caught in a freeze that killed off their prey. But this is drought.

* Now for a bedtime story. Emphasis/paragraph interruption is mine.

Moisture as a determinant of habitat quality for a nonbreeding Neotropical migratory songbird

Smith et al

Abstract.
Identifying the determinants of habitat quality for a species is essential for
understanding how populations are limited and regulated. Spatiotemporal variation in moisture and its influence on food availability may drive patterns of habitat occupancy and demographic outcomes. Nonbreeding migratory birds in the neotropics occupy a range of habitat types that vary with respect to moisture. Using carbon isotopes and a satellite-derived measure of habitat moisture, we identified a moisture gradient across home ranges of radio-tracked Northern Waterthrush (Seiurus noveboracensis). We used this gradient to classify habitat types and to examine whether habitat moisture correlates with overwinter mass change and spring departure schedules of Northern Waterthrush over the late-winter dry season in the tropics. The two independent indicators of moisture revealed similar gradients that were directly proportional to body mass change as the dry season progressed.

Birds occupying drier habitats declined in body mass over the study period, while those occupying wetter habitats increased in body mass. Regardless of habitat, birds lost an average of 7.6% of their mass at night, and mass recovery during the day trended lower in dry compared with wet habitats. This suggests that daily incremental shortfalls in mass recovery can lead to considerable season-long declines in body mass. These patterns resulted in consequences for the premigratory period, with birds occupying drier habitats having a delayed rate of fat deposition compared with those in wet habitats.

Taken together with the finding that males, which are significantly larger than females, are also in better condition than females regardless of habitat suggests that high-quality habitats may be limited and that there may be competition for them. The habitat-linked variation in performance we observed suggests that habitat limitation could impact individual and population-level processes both during and in subsequent periods of the annual cycle.

The linkage between moisture and habitat quality for a migratory bird indicates that the availability of high-quality habitats is dynamic due to variation in precipitation among seasons and years. Understanding this link is critical for ascertaining the impact of future climate change, particularly in the Caribbean basin, where a much drier future is predicted.

---

So what does that all mean? It means, indirectly, that birds overwintering in dry places [here] may not have built up enough energy stores to migrate back north. Or if they have, by the time they get there they're not going to be able to compete as well as birds who wintered in areas with higher moisture. Or, perhaps, if birds who live in this area haven't had a good rain since September, there are few bugs to eat and a lot of competition. It means that 7.6% (this varies by species, I've seen 22% noted on winter studies) of their body mass goes away every night regardless of whether or not there's a bug to be eaten in the morning.

And in closing, this is a Western Tanager who was either roadkill or emaciated but who had been around long enough for me to not want to investigate further. One hopes that his kin have fared better.

Birding Marathon; look down!

Unfortunately the drought has put a phenomenal amount of pressure on all of the wildlife out here, but interesting things are turning up. The Varied Bunting pictures below were taken on Thursday, May 19 at a private residence in Marathon. This morning, Saturday the 21st, a tailless (??) Brown Creeper was seen on the north side of town, just to the NW of the 'Double Bacon' property line. No photos, alas. Everything is low. Everything is close to the ground, if not on it. The creeper was never more than five or six feet above the ground when we watched it. The Western Wood-Pewee in the yard rarely perches higher than the 4' fence posts.






























Varied Bunting (Passerina versicolor) by Cheryl Wallace

While many critters are being pushed closer to humans (and associated water sources), some simply are unable to survive. Two pristine specimens were picked up this morning, a male Audubon's Yellow-rumped Warbler and an adult male Scott's Oriole. While the Yellow-rump was suspiciously in front of a window, the window was covered with a screen and there wasn't so much as a ruffled feather on the bird. The Scott's could have perhaps hit a barbed wire fence, but it was also in perfect shape, just awkwardly posed in rigor. Both birds, when breast/belly feathers were ruffled for closer examination, showed muscle atrophy, no fat reserves and a sharply protruding keel/breast bone. Each bird relies on moisture, the warbler for the insects and the oriole for the nectar.

So whether the bird is dead or alive, unless it's riding a thermal, look down. Nooks and crannies and shady spots and wet spots and anywhere insect life may be, there's likely a bird nearby. Hopefully we'll get some rain soon and the warblers can go back to the treetops, but for now they're all grounded.