July Flowering Phenology

by Carl Strang

Before July, first flower dates had been running about 2 weeks early this year. Past experience led me to expect that the interval would drop as the summer progressed. So, what actually happened at Mayslake Forest Preserve?

Compared to last year, 37 species bloomed a median 10 days earlier in July, a week less than June’s difference. The range was 48 days earlier to 22 days later. The gap with 2010, which also had been a relatively early year, was down to a median 6.5 days earlier in July (vs. 8 for June), the range for 30 species was 32 days earlier to 28 days later. The difference was back up, to 12.5 days, in the comparison to 2009 (28 species, range 39 days earlier to 20 days later). That difference was 19 days in June.

Blue vervain was the most representative species in July, blooming 13 days earlier than last year, 10 days earlier than in 2010, and 13 days earlier than in 2009.

Naturally I expect the difference to drop still more in August.

Swamp Cicada Confirmed

by Carl Strang

Two years ago I was positive that I had heard swamp cicadas at Springbrook Prairie Forest Preserve, and posted about it in this blog. The habitat and song were right. However, I had not seen any of them, failed to hear any when I checked the site last year, and doubts developed as I noticed how percussive are some songs of Linne’s cicada, our most common summer species. On Saturday morning I returned to Springbrook for another try (this cicada is mainly a morning singer). I heard a distant cicada that sounded right, and made my way to a pair of small isolated mulberry trees.

They were in a dry location elevated above the stream that was converted from a straight ditch to a proper meandering configuration a few years ago.

I came in too quickly and the cicada flushed, but he simply flew to a new perch higher in the same tree. He resumed singing, and I was able to get a good binoculars view. The swamp cicada, unlike most of our members of genus Tibicen, is physically distinctive. It is largely black, with some green about the head and brilliant white spots on the sides of the abdomen. I was able to confirm the identification, and brought out the camera.

Not the sharpest photo, but sufficient to document the identification.

As singing cicadas often do, he changed his location slightly every few songs.

Here’s a side view. Note that he has lowered his beak.

I was able to get good recordings of the songs, too. I feel confident now that I can identify this species by song. It is based on a pulsing vibrato like that of Linne’s cicada, but is distinctively percussive. Though some individual Linne’s have a hard quality to their vibrations, it is not as sharp, and the sound quality is different. To my ear, the swamp cicada’s song is reminiscent of a rapidly struck tambourine. You can hear an example at the Songs of Insects website.

The significance of this is that the swamp cicada is not supposed to occur this far north in Illinois, though it does so farther east. The swamp cicada joins other species including the broad-winged tree cricket, jumping bush cricket, and round-tipped conehead as singing insects that have extended their range to the north in recent decades. Note: older references give chloromera as the species name for the swamp cicada, but more recent ones have been calling the species Tibicen tibicen.

Some Bird Notes

by Carl Strang

There had been no sightings of Mayslake Forest Preserve’s great horned owl fledgling since the day after it left the nest tree.

One of my last views of it, on May 3.

On Saturday evening I was at Mayslake to see First Folio Theater’s production of Shakespeare’s Merchant of Venice on the outdoor stage. During the intermission I took a quick walk to the east end of the preserve, and was rewarded by the peculiar screeching whining contact calls of a juvenile great horned owl. Still flapping!

Another owl update was this newly molted feather I found during last week’s creek walk.

Proof that the barred owls are in their usual territory at Waterfall Glen Forest Preserve.

Earlier in the season one of Mayslake’s willow flycatchers gave me a photo op.

This is a bird of open fields with scattered shrubs. Usually one pair nests at Mayslake.

Birds are much quieter now that the breeding season is nearly done.

Recent Maylake Insects

by Carl Strang

Today’s post accomplishes some catch-up on insect observations at Mayslake Forest Preserve. Familiar species have returned. Eastern amberwings have been especially abundant this year.

The male is well named, his wings a solid amber color.

Less abundant but always a welcome sight is the dogbane beetle.

The jewel-like iridescence makes this species stand out.

Earlier in the season I found some LeConte’s haploas in the stream corridor prairies.

This is the second member of its genus to appear at Mayslake, the other being the reversed haploa.

Another species commonly visiting flowers proved to be easy to identify.

Archytas apicifer has a shining blue-black abdomen and a striped olive or gray thorax. It has been an abundant flower feeder this year.

This fly is a parasite of caterpillars, laying its eggs especially on those of the noctuid family.

Drought Ended?

by Carl Strang

The drought that characterized the first half of summer was broken locally by a series of thunderstorms. The contrast was clear when the time came for the Roger Raccoon Club creek walk at Waterfall Glen Forest Preserve. In the first session there had been no water flowing.

Sawmill Creek on June 27.

Last week all had changed.

The kids could explore and hunt for critters in the entire length of stream, rather than just a few pools.

As for the stream corridor marsh at Mayslake Forest Preserve, on Monday I found that dense vegetation was growing in the basin’s damp soil.

There still was no surface water, however.

Much more rain needs to fall to compensate for what was lost earlier. In the case of the marsh, additional rain will need to exceed the transpiration by all those plants.

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