Speak for the Trees

An Eared Grebe far from the salt lakes settles on Morse Reservoir

An Eared Grebe (*Podiceps nigricollis*) has been sitting on the water at Morse Park, on the shore of Morse Reservoir in Noblesville, since at least the second week of September. Birders have reported a single bird there thirteen times, most recently on September 14. This is a western bird. Eared Grebes nest on prairie marshes and shallow alkaline lakes from the Dakotas west to the Sierra, and most of them never come this far east. In central Indiana the small grebe that usually shows up on the reservoirs in fall is the Horned Grebe, and by mid-September the two look alike enough that the differences matter. Both have shed their breeding colors; the Eared Grebe's black neck and gold ear tufts are gone by now. What is left is a dusky little diver with a peaked crown. The peak sits at the center of the head on an Eared Grebe and toward the back on a Horned Grebe. The Eared Grebe's forehead rises steeply, its neck is thinner, and its bill is finer, with the lower edge angled slightly upward so the whole bill looks tipped up. Its face is the best mark at a distance: on a Horned Grebe the white cheek and neck are clean and bright, with a straight border against the dark cap; on an Eared Grebe the gray bleeds down into the cheek and the neck stays gray rather than white. An Eared Grebe also rides with its rear end cocked up out of the water, which a Horned Grebe does not do. How this species spends its autumn is unlike almost any other bird. From late summer into November nearly the whole North American population, close to 99 percent of it, flies to two salt lakes, Mono Lake in California and Great Salt Lake in Utah, to feed on brine shrimp and alkali flies. There each bird more than doubles its weight, from around 260 grams to over 600, while its digestive organs swell and its chest muscles shrink by about half. The birds become flightless for three to four months while they fatten, then rebuild the flight muscles and leave for the Gulf of California and the Salton Sea. Because a version of this cycle repeats several times a year, the Eared Grebe spends roughly nine to ten months of each year unable to fly, longer than any other bird that still flies at all. The bird at Morse Park is not doing any of that. There are no brine shrimp in a freshwater reservoir, so it is diving with its feet for what the impoundment offers: small fish, insect larvae, and small crustaceans. It flew here and will have to fly on, so its chest muscles are intact. It is a bird that peeled away from the movement toward the salt lakes, or was never headed there, and settled on the largest open water it could find in a county of till-plain farmland and subdivisions. Morse Reservoir is a dammed stretch of Cicero Creek, and to a grebe that is what matters: deep enough to dive in, wide enough to be seen from and to leave from. Anyone checking from the park should look for a lone, low-floating bird well out from shore, smaller than a coot, diving often and staying down long. If it is still around, the face pattern and the tipped-up bill will settle the identification.

A dry year on dry year tests spruce, aspen and trout alike

The water year closes in two weeks, and the tally for the headwaters above these forests is close to set. The three snow-survey stations that measure what falls on the high country here, Burro Mountain 11 kilometers away at 9,290 feet, Bison Lake 24 kilometers out at 10,950 feet, and Trapper Lake 42 kilometers out at 9,750 feet, have taken in 78, 79 and 70 percent of their median precipitation for the year so far. All three are bare of snow, and the accumulation season at these sites does not begin until late October. Barring a wet last half of September, those numbers stand. In Garfield County, this same week last year, extreme drought covered the whole county and none of it was in the exceptional category, the most severe one on the map. Exceptional drought stayed absent through the winter, appeared across a quarter of the county in the last week of March, spread to three-quarters by late April, and held near half the county from late May through August. As of the week of September 8 it covers 34 percent of the county. Ninety-seven percent remains in extreme drought or worse, as it has for nine weeks running. A dry year following a dry year matters more to the trees here than either year alone. Engelmann spruce fight off spruce beetle with resin, and a tree's ability to produce it depends on water. Tree-ring reconstructions of past outbreaks in northwestern Colorado spruce forests, published in the journal Ecology by Hart, Veblen and colleagues, found that outbreak timing tracked drought more closely than it tracked temperature. Experiments on Engelmann spruce found photosynthesis falling off once stem water potential dropped past a threshold under both short and chronic water stress. A spruce that spent last summer drawing down its reserves enters this one with less to spend. Aspen fail differently: severe drought cavitates the vessels that carry water from root to leaf, and the stands most exposed are the low, south-facing ones. Weakened aspen then draw poplar borers, aspen bark beetle and Cytospora canker. The fire season followed the same curve. The Dry Creek Fire burned 315 acres south of Rifle in late June. The Elk Knob Fire, a lightning holdover in the Flat Tops Wilderness, was contained August 19. The Derby Fire near the Flat Tops prompted evacuation notices around August 20. By mid-September the whole of the White River National Forest was under Stage 1 fire restrictions, which bar campfires anywhere outside developed sites, with the Forest Supervisor noting that conditions remain dry, particularly at the higher elevations. Satellite fire-detection systems, which flag heat signatures from active burns, have shown no such detections within 50 miles in the past five days. In the creeks, the USGS streamgauge on Elk Creek at New Castle read 1.33 cubic feet per second this morning, down from 16.5 a month ago. That gauge sits at the valley mouth around 6,800 feet, below irrigation headgates that stay open on the Western Slope through October; it reads what is left of the creek after diversions, not the headwater flow itself. Brook trout in the Flat Tops drainages spawn once water drops below 9 degrees Celsius in October, and their eggs need groundwater moving up through clean gravel to stay oxygenated. Low fall water can cut fish off from those sites and starve the gravel of flow. Native cutthroat trout, logged on iNaturalist last October along Mitchell Creek near Glenwood Springs, run a narrower thermal window, with mortality setting in above roughly 19.6 degrees Celsius. The Middle Colorado Watershed Council, based in this stretch of the Colorado River valley, tracks streamflow, forest condition and fire risk across this drainage.

Sonoran Desert Tortoises are out across the Tucson basin this monsoon

Sonoran Desert Tortoises (Gopherus morafkai) have been out on the ground across the Tucson basin from mid-August into the second week of September, most of them in the Avra Valley west of the city and a smaller set on the rocky slopes below the Catalinas. This is the one stretch of the year when the odds of meeting one on a trail are good. The animal spends most of its life underground or under rock, and it comes out mainly in daylight during the monsoon, when the rain has greened up the forage and filled the shallow pools it drinks from. It is a domed, high-backed tortoise the color of the caliche it digs into, with a shell somewhat narrower and more pear-shaped than the Mojave desert tortoise's. The two species are split by the Colorado River and do not overlap here, so any wild tortoise on this side of the river is the Sonoran one. It favors steep, rocky ground and the bajadas below it, not open valley floor, and it shelters in burrows it digs itself, in caliche caves, and in rock crevices. The tortoise drinks from puddles a finger deep by putting its nostrils to the surface and pulsing its throat to pull the water in. It also scrapes basins in the soil to catch rain and remembers where they are, walking directly to them when a storm passes. What it takes in goes into a bladder that can hold water for extended periods and release it back into the bloodstream as the body needs it. When a rain finally comes after a long dry spell, a tortoise drinks heavily, voids the concentrated urine it has been carrying, and stores fresh water in its place. In a hard drought an adult can go a long time without drinking. It eats plants only, leaning on annual wildflowers first and then grasses and cactus, with prickly pear fruit taken whenever it is ripe. September is also hatching season. Eggs laid in early summer, buried in the floor of burrows, hatch in September and October, though some clutches hold over and hatch in spring. A hatchling is about the size of a silver dollar and soft-shelled for years. Only a small fraction reach adulthood. Those that do mature between 13 and 20 years old and can live 50 to 80 years, which means a tortoise crossing a trail this week may have been crossing the same slope since before the surrounding subdivisions were built. Breeding peaks in August and September as well, so two adults seen together right now are likely a courting pair. iNaturalist flags the species as threatened, but the U.S. Fish and Wildlife Service reviewed it and found in 2022 that federal listing was not warranted, and it does not appear on the current federal list for this area. The pressures on it are the same either way. Buffelgrass, an introduced African grass now widespread around Tucson, burns hot enough to kill saguaros and palo verdes on slopes that never evolved with fire. The tortoise needs an unburned desertscrub slope with rock to hide in and annuals to eat after rain. Anyone who finds one should leave it where it is. A tortoise picked up or frightened may void its bladder, and in a dry year that is the water it was counting on to get through to the next storm.

Six weeks of drought cure a prairie ahead of schedule

Severe drought now covers nearly nine-tenths of El Paso County, and it got there in about six weeks. In the second week of June the U.S. Drought Monitor had none of the county in severe drought or worse. By mid-June 12 percent was. By the first week of July it was 58 percent, by the end of July 93 percent, and by the middle of August 97 percent. Extreme drought, the next category up, went from none at the end of June to 65 percent of the county in the week of August 11. The latest map, for the week of September 8, puts 90 percent of the county in severe drought or worse and 40 percent in extreme drought. The retreat of the extreme category since mid-August is the only movement toward wet. County-wide August rain came to about 2.1 inches, half an inch under the 1901-2000 average, enough to pull part of the county back from extreme to severe but not enough to move the severe line. September has added nothing. Colorado Springs Municipal Airport, 12 kilometers from the grasslands, has measured no precipitation this month against a normal of 0.63 inches, and its average daily high over the past 30 days was 86.9 degrees, 7.4 degrees above the 1991-2020 normal for those dates. The timing lands on the grasses that define this ground. Blue grama, sideoats grama, big bluestem and little bluestem are all recorded across Bluestem Prairie Open Space, and all four are warm-season grasses that flower and fill seed from July into September. The drought set in during the first week of July, at the start of that window. These grasses answer dry soil by letting the leaves brown and drawing sugars and nitrogen down into the crown and roots, where the buds for next year's tillers sit. Seed heads that had already started can finish on stored reserves. New tillers and root growth stall. Blue grama's production on the shortgrass steppe tracks growing-season rainfall far more than temperature, so a summer that turned dry in early July is a summer of short growth no matter how warm it ran. From the trail this reads as a prairie that cured early. Warm-season grasses brown every fall, and this year the drought pushed that turn ahead of the calendar. The open question is next spring. Regrowth after rain comes slower where the crown reserves were spent getting through the dry spell, and how much of that happened here depends on what falls between now and the first hard freeze.

A wryneck passes through Beddington on its way south

A wryneck stopped at Beddington Farmlands last week, one bird, reported on 10 September among the grassland, scrub and lakes being built back on the old sewage-farm ground beside the Wandle. It drew a steady line of birders, which is the usual reception for this species in Britain now. The wryneck (Jynx torquilla) is a woodpecker that does not act like one. It is a little larger than a sparrow and slimmer than a song thrush, grey-brown all over, barred and mottled so finely that a bird sitting still reads as a piece of bark. A dark stripe runs from the crown down the back. The tail is square and grey, and its feathers are soft rather than the stiff props a great spotted woodpecker braces itself with, so a wryneck does not climb trunks. The bill is short and pointed, made for probing soil, not chiselling wood. Look for it low: on a path edge, a bare patch, the foot of a bramble. It moves with slow, jerky hops, flicks its tail and keeps turning its head. When cornered it twists its neck round in a slow, snake-like writhe, and that habit gave it its name. It lives almost entirely on ants. Photographs at Swiss nests found ants in 95 percent of feeds, and most of what the birds carried in was not workers but larvae and pupae, dug straight out of the nest chamber. It reaches them with a sticky tongue that extends something like ten centimetres beyond the bill on a bird under twenty centimetres long. The ants it takes most in Europe belong to genera such as Lasius and Tetramorium, colonies that sit in warm, dry, bare ground or under short turf, which is why a wryneck's whole life turns on the presence of open ground it can get its tongue into. On migration it will use almost any open place with a few bushes, including ground with no trees at all. Beddington, with its rough grassland, scrub edges and the disturbed earth of ongoing restoration, offers that kind of ground, though the record does not say what the bird was doing there. Nearly every wryneck seen in Britain now is a passage bird. They move between breeding grounds in Scandinavia and wintering grounds in Africa, and they turn up here on easterly winds, mostly in September, mostly on the east coast, with a scatter inland like this one. The British Trust for Ornithology puts the annual total at around 360 birds. Two centuries ago the wryneck bred across southern England. The last English pair nested in 1985, a few hung on in Scotland into the early 2000s, and the species is now considered extinct as a British breeder. The leading explanation is a loss of the bare ground and short vegetation its ants need, along with intensified farming and pesticides, but the case is not closed; the bird has also fallen steeply across western and central Europe while holding on in the east and south, and some researchers suspect the problem lies partly on the African wintering grounds. A single bird hopping through a restoration site in September is what the species now looks like here: passing, briefly, on ground that happens to be open.

Yellow-legged Hornet spotted at Waldshut, a river-crossing from Zürich

A Yellow-legged Hornet (*Vespa velutina*) was photographed near Waldshut, on the German bank of the Rhine, in the last week of August. This is the introduced Asian hornet that Swiss cantons have been asking the public to report, and Waldshut is a short flight across the river from the Unterland woods around Bülach, Eglisau and Kloten. The native European Hornet (Vespa crabro) is the thing it gets confused with, and size does not separate them. Colour does. The Yellow-legged Hornet is a dark insect. Its thorax is velvety black. Its abdomen is mostly black, with a single broad orange band on the fourth segment and a thin orange line nearer the waist. Its legs are dark down to the middle and then bright yellow to the tips. The European Hornet, by contrast, is a warm-coloured insect. Its thorax is reddish-brown. Its abdomen is largely yellow, with black markings on the front segments. Its legs are brown all the way down. The leg tips are the quickest check. Yellow feet on a dark hornet mean the Asian species. The colony is an annual structure. A mated queen wakes in March and builds a small paper nest in a sheltered spot, often on or in a building; the primary nest the City of Zürich removed in Witikon last year was in a shutter box. Once the first workers emerge in June the colony usually moves to a second, much larger nest high in a tree, often above ten metres, which can reach 60 centimetres across and hold around 2,000 workers at once. Mid-September is when these colonies are at their largest and are producing males and next year's queens. The big nests are almost impossible to see against summer foliage. Most of them are only found after the leaves drop in October and November, and by then the new queens have usually already flown. Those queens spend the winter alone in soil, in rotting logs and stumps, or under loose bark, exactly the material a broadleaf forest floor supplies. Everything else in the nest dies with the frost. The hornet earns its reputation at beehives. Workers hover at the hive entrance and snatch foragers coming home with pollen or nectar, drop them to the ground and paralyse them. Bees under this pressure stop leaving the hive, honey yields fall, and winter losses rise. It is not only a bee predator, though. A study of 16 nests in southwest France found honeybees made up about 38 percent of prey, flies about 30 percent and social wasps about 20 percent, with 159 prey species in all; colonies in forest took more wasps and colonies in towns took more honeybees. Bumblebees and solitary bees were a very small share. A single colony is estimated to take roughly 11 kilograms of insects over a season. The regional picture comes from the cantonal authorities rather than from this one sighting, and the figures below reflect how much reporting effort has gone into finding and logging nests, not necessarily how the population itself is changing. Canton Zürich received about 100 reports through the national platform in 2025. The City of Zürich removed a primary nest in Witikon and a secondary nest at a forest edge in Schwamendingen last year, and by mid-July this year had already logged four primary nests. A nest was also found in the Eigental reserve near Kloten, and the canton says it is now drawing up criteria for which nests to destroy first in sensitive habitats. Canton Aargau, further along the Rhine, had sightings of the hornet as early as 2022 and 2023. Anyone who sees a dark hornet with yellow feet on the Swiss side can report it, with a photo, at asiatischehornisse.ch; on the Baden-Württemberg side, the state nature conservation administration runs a reporting portal. Spring is when the small primary nests on buildings are easiest to find and remove, but the coming weeks of leaf fall are when the big canopy nests finally show themselves.

Gunnison County reaches exceptional drought as Tomichi Creek thins

Half of Gunnison County is now in exceptional drought, the most severe category the U.S. Drought Monitor uses. In the week of September 8 the share of the county rated exceptional jumped from about 22 percent to just over 50 percent. The other half of the county is in extreme drought. For the first time this year, none of the county is rated any better than extreme. The severity had been flat for most of the summer. From mid-August through the end of the month, about 80 percent of the county sat in extreme drought or worse and about 22 percent in exceptional. The first week of September pushed the extreme-or-worse figure to 91 percent. The second week took it to 100 and more than doubled the exceptional share. Two weeks did what the previous two months had not. The Drought Monitor's own description of the exceptional category is exceptional and widespread crop and pasture losses, with shortages of water in reservoirs, streams and wells creating water emergencies. Statewide this season, 64 percent of Colorado's pasture and rangeland is rated in poor or very poor condition, against a five-year average of 23 percent. That is a statewide number, not a Gunnison Basin one, but the basin's hay meadows and upland sagebrush are inside it. The shortfall starts high above the basin. The Butte snow station, at 10,190 feet about 24 miles from Gunnison, has recorded 18.6 inches of precipitation since the water year began last October, 74 percent of its median for the date. Cochetopa Pass, at 10,020 feet about 32 miles out, has recorded 11.7 inches, 70 percent of median. Those are precipitation totals, not snow on the ground; both stations are bare in September as they always are. Tomichi Creek runs on that mountain water. It peaks in late May or early June and recedes through the summer, with several small irrigation diversions drawing from it along the way. The gauge on Tomichi Creek at Gunnison read about 20 cubic feet per second this week, on a creek that still has a month or more of recession ahead of it before winter. Brown trout are the fish most exposed to a thin September flow in this reach. They spawn in fall, from September into December, once the water cools into roughly the 41 to 54 degree range, and they need enough depth and current to reach clean gravel and keep a nest of eggs watered and silt-free through the winter. A creek reduced to shallow riffles and separated pools blocks that movement and leaves whatever gravel is used at risk of drying out. Water near the Gunnison gauges was running around 54 degrees this week, which is comfortable for trout. The trouble with a small volume of water is not that it is warm now; it is that it heats and cools faster across a day and loses its buffer against low oxygen. The case-building caddisflies logged along these streams through August do the coarse work of shredding the leaves that are beginning to fall into the channel now, and they need cool, continuously moving water over gravel to do it. Satellite passes this week show no cluster of fire detections within 30 miles of Gunnison, only a single weak nighttime pixel near Crested Butte that could be almost anything. The sagebrush is going into dormancy dry, with grasses and forbs beneath it cured, and that is the fuel that carries fire through sagebrush country. The next Drought Monitor map comes out September 18.

Garganey return to Kavdi Pat, right on schedule

Garganey are back on the Mula-Mutha at Kavdi Pat, the stretch of river about fifteen kilometers downstream of Pune where the road from Hadapsar ends in paddy fields at the water. Five were counted there on September 8. They are the first of the wintering ducks to reach this reach of river, and they are on schedule; Garganey (Spatula querquedula) are among the earliest ducks to arrive in India each autumn and among the last to leave, with some staying on peninsular wetlands into May. Anyone going to look for them should not expect the bird on the field guide plate. The drake's white stripe curving from the eye down the back of the head and his pale grey flanks belong to breeding plumage, and he is not wearing it now. After nesting the males moult into a drab eclipse plumage and keep it well into the winter. In September the whole flock reads as streaky brown ducks. The drake keeps a slightly stronger head pattern and a whitish chin, and when he stretches or flies he shows a pale blue-grey forewing. That forewing is the mark. Common Teal, the other small brown duck on this water in autumn, flies on a dark forewing with a green speculum. On the water the Garganey is a little larger than a teal and carries a heavier, all-grey bill. Its head is more strongly striped: a pale eyebrow over a dark eye-stripe, a pale patch at the base of the bill, and a clean whitish throat with no streaking. Indian Spot-billed Ducks share this river all year and are easy to separate, roughly twice the bulk, with a black bill tipped yellow and a red spot at its base. Garganey are dabblers. They feed swimming with the head under, picking from the surface, or upending in water a few inches deep, and they take seeds, pondweed, roots and shoots along with worms, snails, crustaceans and insect larvae. They often feed at night and rest through the day, so a daytime count can miss birds tucked into the reeds. The birds reaching Pune have migrated in from breeding grounds well to the north, arriving early as Garganey typically do. What they find at Kavdi Pat is a low-gradient stretch of river where the channel spreads into shallow pools, sandbars, mudflats and reed beds as the monsoon flow drops. As the river recedes through October and November, the shallows fill with algae, sedge, small fish and insects, and the ducks and waders gather in numbers. Five Garganey in the second week of September is the beginning of that season.

Red-legged frogs settle into summer refuge as bullfrogs share their hills

Early September is the part of the year the California red-legged frog (Rana draytonii) spends away from water. Breeding ran from November into April. By now most adults have left the ponds and moved into the surrounding hills, sitting out the dry months under rocks, in leaf litter, in animal burrows, or down in the cracks of a pond bottom that has already dried. A frog can travel a mile overland in wet weather and settle two miles from where it bred. The sightings logged this month, from the park canyons of San Francisco down the Pacifica shore around Sharp Park and north across the Golden Gate into the Mount Tamalpais hills, are single frogs in refuge, not a gathering at any one pond. It is the largest frog native to California, up to four and a half inches from snout to rump. The back is reddish brown to olive with irregular dark blotches. A raised ridge of skin runs along each side from behind the eye to the hip. A dark mask crosses the face above a pale stripe on the upper lip. Turn one over, or catch it mid-leap, and the belly and the undersides of the hind legs are washed in red; that is the name. Young frogs may show yellow there instead of red, with heavier spotting on the back. Two other frogs share these hills. The Sierran treefrog is a fraction of the size, two inches at most, with toe pads and no side ridges, and it owns the loud two-part ribbit of the movie soundtracks. The red-legged frog's own call is a low, stuttering grunt that carries poorly. The American bullfrog is the one to look at hard. It is bigger, green about the snout, with a very large eardrum behind the eye, and it lacks both the side ridges and the pale lip stripe. Its call is the deep jug-o-rum. The bullfrog matters for more than identification. It was introduced to California, it breeds over a longer season, and its tadpoles eat red-legged frog eggs and tadpoles. In one study, red-legged frog larvae sharing a pond with bullfrog tadpoles survived at under five percent, against thirty to forty percent where bullfrogs were absent — the proposed mechanism is direct predation by bullfrog tadpoles and juveniles on red-legged frog eggs and larvae, plus competition for the same shallow-water habitat. Not every study finds that pattern; some point out that bullfrogs tend to turn up where ponds have already been altered, so the two effects are hard to pull apart. Bullfrogs were logged through the same weeks this summer around Mill Valley and Lake Lagunitas, in the same Marin hills as one of this month's red-legged frog records. Whether the two share any particular pond is not something the records show. What the red-legged frog needs from a pond is specific. Eggs go into shallow water at the vegetated edge in loose clusters and hatch within two weeks. The tadpoles then take three and a half to seven months to become frogs, so a breeding pond has to hold water from winter into summer. It also has to stay cool. The frog cannot survive water above 29 degrees Celsius (about 84 F), and ponds with willows and cattails standing over deep water do best. The emergent plants do double duty: they hide tadpoles from herons and fish, and they warm the shallows enough to grow the algae the tadpoles feed on. The species is listed as threatened under the federal Endangered Species Act, and mapped critical habitat overlaps the Peninsula. Anyone who finds one of these frogs this fall, under a board or beside a seep well away from open water, is seeing the non-breeding phase that can take up as much as eleven months of its year.