Tag: graphic

I took part in a Clifton Institute bioblitz on the property of an institute sponsor. I didn’t know quite what to expect, or what to focus on, so I walked along with the group, recording observations of what looked interesting to me, some of which I had to key out at home.

The woods have been logged over recently, and show evidence of disturbance: a fair amount of non-native invasives, as well as Indian Tobacco (Lobelia inflata), about which the Flora of Virginia says, “In a wide variety of mesic to dry forests and woodlands, depression wetlands, flood-scoured shores and bars, clearings, fields, roadsides, and other disturbed habitats.”

There seemed to be some disagreement among the group about this Swamp White Oak (Quercus bicolor). I’m not sure why. Seems obvious to me.

Flipping rocks, the group found three Eastern Wormsnakes (Carphophis amoenus amoenus). White and White write, “This snake does not bite when handled but will try to escape by probing its head and tail into the captor’s hand searching for a way out,” which is just what this li’l fellow is doing in Ben’s hand.

At the lights, most of the group focused on moths and caddisflies. I’m just getting started with moths—I’ve never before seen moth eyeshine—so I spent more time getting to know some beetles on the groundcloth, like this handsome darkling beetle, Alobates sp.

Rea was giddy when she found this late-instar Regal Moth (Citheronia regalis). The larvae have the common name Hickory Horned Devil.

I took the opportunity to practice using my audio recorder. Need to work on setting levels and generally using it more before I splurge on field headphones and a shotgun mic.

Observations are still coming in.

My final report for the ducks and mergs team this season:

Well, our box score for the season shows a lot of at-bats but not too many runs across the plate. The mergansers started 10 clutches but only hatched 4; the Wood Ducks started 5 but only completed 1. We had evidence of predation in only 1 box (raccoon, #60). A possible hypothesis to explain the high rate of nest abandonment by the mergansers is simply that there were too many birds chasing scarce resources.

The egg and hatchling counts are similarly depressed: 139 eggs laid by the Hooded Mergansers, with 52 hatched (37%); 34 eggs laid by the Wood Ducks, with 7 hatched (21%). Summary worksheet from our monitoring.

A recap of the boxes: I applied some insulating foam to patch gaps in boxes #1 and #3. Boxes #4 and #7 should be replaced. A map of nest box locations.

Tiny little box #5 was put to good use this year! It was the site of our single successful Wood Duck nest. During (10 June) at left and after (24 June) at right.

Monitors, thank you for all your help!

From my summary report to the team:

As for predation by the snakes, I wouldn’t move any of the boxes just on the evidence of this season. Last year it was boxes #1 and #3 where we had a problem; this year it was #7 and #62.

Local conditions around box #69 have changed. Past years, it was overrun with Typha sp. by mid-May. This year, it remained clear of veg.

As for nest structures for Mallard and American Black Duck, let us know where you’ve placed them and we will try to work them into our monitoring routine. My references show that the nesting season for these birds extends later into the summer, so we would have the opportunity to extend our work season.

A pattern that I’ve noticed over the years is that the fledge-to-eggs ratio for Hooded Merganser is usually higher than that for Wood Duck. A couple of hypotheses:

(1) Since the mergs start laying eggs a little earlier than the woodies, perhaps they out-compete them and occupy the more favorable boxes for that year. (We don’t see that one species is particularly faithful to a box, and indeed since we see a few mixed clutches, a box may be considered favorable by both species.)

(2) We are more likely to see “dump” and “drop” nests for the woodies: boxes with 20+ eggs. And with these jumbo clutch sizes, it’s more difficult to incubate all the eggs sufficiently.

We wrapped up the nesting season two weekends ago. The Wood Ducks bounced back after a couple of slower years. I’ve noticed a pattern recently: not only do the Hooded Mergansers get started earlier, but overall they tend to fledge a greater percentage of the eggs they lay—85% or better, seven of the last nine years. The Wood Ducks, on the other hand, are subject to dump/drop nests that don’t fledge anything. (One such nest a year is typical for us, out of 15 to 20 boxes being monitored.) In six of the same past nine years, our fledging rate for woodies has been 67% or lower.

The sanity-checker script at NestWatch is skeptical that we have mergs laying 14 eggs in a clutch, and laying as early as the last days of February. I invite the Lab scientists to come check the boxes for themselves.

I took a new camera with me to the park: it’s still a happy snap, but the optical zoom is better suited for quick shots of butterflies. The spangles on the underside of the hindwing of a Speyeria cybele are not usually the first thing you see, but they are diagnostic for ID.

Paul and I checked all the boxes last week and counted eggs for the remaining three nests. Swamp Rose (Rosa palustris) was in bloom, attended by various pollinators and other hangers-on.

The Hooded Mergansers continue to be more successful in our 16 boxes. We saw 7 clutches that were primarily merg, yielding 103 eggs, hatching 92. The Wood Ducks produced 6 clutches, laying 72 eggs but only hatching 48. Of the 13 total clutches, there were eggs of the other species in 4 of them. Our combined species total of 140 ducklings is the maximum over the 30-odd years that we have data for.

The two boxes that were relocated in preparation for the construction project (#77 and #6) were both successful. Box #13 had eggs
laid in it over a period of about 6 weeks, from 1 March to 13 April. In the end, 11 of the 14 eggs hatched.