Orchelimum Natural History

by Carl Strang

Last week I made reference to Darryl T. Gwynne’s book on katydid mating system evolution. That book led me to other references, including a Ph.D. thesis by Marianne Feaver, who studied the behavioral ecology of three species of large meadow katydids (genus Orchelimum) under the direction of Richard Alexander at the University of Michigan in the 1970’s. I ordered a copy of Feaver’s thesis, and enjoyed reading it over the weekend. There was much richness of detail that will benefit my observations in the coming months and years. Here I’ll just share a few gleanings.

Male black-legged meadow katydid

Male black-legged meadow katydid

Feaver studied black-legged, common and gladiator meadow katydids. Maturation in the three species required 2 months from hatching to adulthood. In northeast Illinois the earliest species, O. gladiator, matures in late June, implying a late April hatch from eggs laid in the stems of plants.

Female gladiator meadow katydid

Female gladiator meadow katydid

Oviposition plants, food and cover are the three most important habitat features in these species. Upon reaching maturity, females move from nymphal areas that emphasize food and cover to places offering the best mix of food, cover and oviposition sites, and the males follow them there. The males then set up circular territories that space them out. These are defended mainly through song, though in high density populations physical combat often can take place. Defensive songs are characterized by increased number and rapidity of the tick portion of the song, the buzz portion apparently not important here. The territorial male reacts to the singing intruder, who may retreat or approach. In the latter case, after repeated warnings, the territory holder is likely to attack. The heavier male generally wins. Territory holding males tolerate silent males, which apparently are waiting for the territorial males either to be removed by predators or parasites, or to mate, after which they must retreat to gain back their weight.

Male common meadow katydid

Male common meadow katydid

They spend the night buried down in low, dense cover, then males begin spacing themselves out in mid-morning, and are singing by late morning. After territories stabilize, singing continues through the afternoon. Females assess and compare males, with mating taking place in the late afternoon. Females may take several days to choose a mate, however, and only mate once. In the early evening they break off to feed, then climb down into cover to spend the night.

This pattern provides a basis of comparison to other species, which will vary in detail. For instance, though I found a freshly mated female dusky-faced meadow katydid in the mid- to late afternoon, as I mentioned last week, that species reportedly does most of its singing at night.

Red-tailed Hawk Species Dossier

by Carl Strang

I have heard reports that red-tailed hawks are starting to carry sticks, and March is the month when they begin to nest in DuPage County, so today I am sharing my species dossier on that raptor. As usual, the rule is that the dossier is limited to what I have observed personally rather than second-hand reports or through the literature.

Hawk, Red-tailed

Red-tailed hawk

This hawk is common in the eastern U.S. They nest in treetops in woodlots, sometimes on utility poles, and forage over nearby fields, soaring, or perching on trees or poles. Unless winter weather is severe, they remain all year round.

28MR87. Hawk carried a snake by the head, body dangling beneath, to treetop.

16JA88. McDowell. A great horned owl flew to a tree on the west bank of the river, just north of where trees thin to a thread of willows, and where a housing development comes down to the river. There’s a top-blown tree nearby, also several large oaks. Then crows began raising a ruckus nearby in another direction, as though pestering a great horned owl. From that direction a red-tailed hawk soared, but they paid it no heed. It circled an adjacent riparian strip, but when the owl finally broke and flew with a flock of 10 crows in pursuit, the hawk fell in between, and also began to chase the owl. Once it got above the owl and swooped at it, brushing the owl’s back with its feet, but about then the crows caught up and chased both raptors down toward where I had seen the first owl perched, now out of my sight.

1MY88. Call a wheezing “preeyarrrr.”

7FE89. A red-tail “visited” Willowbrook’s outdoor animal exhibit. The captive red-tails called, caged crows gave short, uninflected (flat) caws with somewhat sharp beginnings but open ends. These were fairly rapid, but not chattering, and not clearly strung together.

Soaring red-tails usually seem to be patrolling territory rather than hunting.

12JA92. Hidden Lake Forest Preserve. A soaring red-tail gave the k-yer call, over woods. Moments later a second passed over, going in the same direction. Is that call given only when another hawk is in sight?

2DE95. West DuPage Woods. A red-tail called frequently. After 10 minutes I saw a second one, also flying. It seems likely that if one calls, another is in its view.

27JA97. Morning. Snow fairly deep. A red-tail flew over the College of DuPage parking lot with something in its talons, pursued by half a dozen crows. The hawk perched on a flat-topped, wooden light pole, and began plucking its prey while crows sporadically left nearby perches and swooped at it. After 10-15 minutes the hawk flew away, and I checked the feathers, which were scattered in singles and small clumps over a 20×30-foot area: mourning dove. The crow calls resembled the ones they use in owl mobbing, but there were fewer birds and the mobbing was less sustained.

Red-tail fledgling at Mayslake, July 2011.

9DE99. Crows pursued a red-tailed hawk in the northeast part of Willowbrook preserve.

18JL00. Willowbrook. In the early afternoon, a Cooper’s hawk soared low above the marsh and areas east and west of it, while 3 red‑tails soared high. One of the visiting red‑tails called once, but the Cooper’s, which has been resident all summer, called repeatedly.

22AU04. Canadian side of Lake Superior. On a driving journey around the lake I passed through an area where there had been a big fire, and saw there both the first kestrel and the first red-tail of the trip, showing them to be associated with relatively early successional, extensive areas in this part of the northern forest.

20NO09. Mayslake. A pair of adult red-tails circled the west end of the savanna calling frequently, and a third call was coming from within the canopy. Eventually one of the adults flushed out a young red-tail, perched in one of the oaks, and it flew low out of the savanna and south across the lake. This could be the same bird that was perched near the dog parking lot yesterday. Clearly this was a defense of winter territory by the pair. It was not clear whether the young bird called, or whether that was mimicry by a blue jay that was nearby. Last winter a pair of adult red-tails stayed around Mayslake the entire season. They seemed to be investigating nesting possibilities, but ultimately vanished for the summer.

The 2010 red-tail nest at Mayslake

16MR10. A red-tail pair is building a nest at Mayslake, in the stream corridor woods adjacent to the parking lot marsh. They carried small sticks in their beaks while flying. (This pair fledged one youngster from this nest, and it stayed around the mansion grounds area for some weeks in the summer, calling loudly and frequently. In 2011 they did not nest on the preserve; their 2010 nest was used by the great horned owl pair. Apparently they nested nearby, however, as a fledgling came onto the preserve occasionally in the summer, and displayed the same loud calling behavior. The pair has been present on the preserve through February of this year, and I will be watching for nesting activity.)

The noisy fledgling from 2010

19JA11. Mayslake. A red-tail flushed from one of the trees near the chapel was carrying a dead gray squirrel and accompanied by its mate. They flew toward the S stream corridor.

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