Journal archives for September 2023

September 18, 2023

Observing Odonata

Sadly, on some of the sites I use regularly for data on dragonflies and damselflies, there is no weather-related information or even time-of-day information. So I've been stumbling around, trying to figure out when the best times are to observe these creatures.

I have been fortunate several times to find dragonflies at mid-morning, e.g. 9-10:30AM. I've been less fortunate in finding them from around 11:00AM until about 2:00PM particularly on very warm summer days.

In the afternoon, from around 2:00PM until around 3:30 or 4PM, I often see both dragonflies and damselflies. After about 4PM, things seem to settle down again and numbers gradually lessen. I have not been successful in observing/discovering evening-flying dragonflies or damselflies but I know they exist and will keep trying for those.

In late August, around 4PM, it was particularly easy to see the Common Green Darner (Anax junius) in pairs, ovipositing in ephemeral puddles and ponds after we'd had a good amount of rain in previous days. One day around 4PM in early September, I saw 4 pairs of Anax junius (each pair in tandem) ovipositing within 16 cm of each other in the same puddle! As a side note, I wonder how successful this ultimately will be since the puddles really are ephemeral and only present for a few days after a heavy rainfall. We do get more rain in the autumn months, but not enough to keep those puddles filled with water until next summer.

Weather: I've discovered that if there is a "window" of sunny weather between rain showers, that is a particularly good time to go out. When I was at the Cedar Island boat ramp pond, it rained heavily and then quit for an hour. The sun came out and there were a lot of both dragonflies and damselflies flying in the sunshine. It rained again about an hour later and both species disappeared (and so did I). The next day was sunny all day and much less productive than it had been during that window between showers.

Cloudy days aren't much good for observing either, although Ischnura prognata don't seem to care if it's overcast since they are in the shadowy forested swamp anyway.

Spring and the first half of the summer are the best months for damselflies here in NC. After that, they seem to be much less frequently seen with the exceptions of the Ishnura genus (Ischnura hastata becomes much more prevalent in late summer than in early summer - at least here in NC) and onsies-twosies here and there of other species. It seems like once the skimmers (Libellula) become numerous in late July, the damselflies start to dwindle/hide more.

Posted on September 18, 2023 02:59 PM by amypadgett amypadgett | 0 comments | Leave a comment

September 26, 2023

End of the 2023 Odonata Season Notes

It's interesting to me to compare this year (2023) to last year (2022) because they differed widely in the numbers and types of Odonata I observed.

2022
In 2022, we had drought conditions all summer, continuing the 2021 trend. In the swamp, most of the streams had dried up although there were a few of the deeper pools that retained water. There were very few fish and crayfish--so few in fact that birds such as Barred Owls and Yellow-crowned Nightherons were either far fewer in number (the Barred Owls) or simply went elsewhere (the Yellow-crowned Nightherons and other wading birds). There were no successful Yellow-crowned Nightheron nests such as there had been in previous years.

However, the Odonata population was huge.
We had large numbers of skimmers everywhere, particularly the Great Blue Skimmer (Libellula vibrans); Slaty Skimmer (Libellula incesta); Bar-winged Skimmer (Libellula axilena); Painted Skimmer (Libellula semifasciata); Golden-winged Skimmer (Libellula auripennis); and Needham's Skimmer (Libellula needhami). You literally could not walk anywhere without seeing most of these skimmers.

In addition, of course, were the Blue Dashers (Pachydiplax longipennis), Eastern Pondhawks (Erythemis simplicicollis), and Common Whitetail (Plathemis lydia). Those were ubiquitous.

In the grass everywhere were Fragile Forktails (Ischnura posita) and Citrine Forktails (Ischnura hastata). In the shadier areas of the swamp along the streams (even though they were mostly dried up and simply mud) were dozens of Furtive Forktails (Ischnura prognata).

There were also spreadwings and other damselflies.

I believe a number of factors were involved, including:

  • They were concentrated in areas where there was still water or attracted to our area because we did have a few pools remaining of water.
  • Other species such as fish and young crayfish were few and far between, thereby reducing the number of predators of Odonata nymphs.

2023
In 2023, we started out in drought conditions but by mid-summer, we started to get more rain which filled the streams in the swamp as well as filling ephemeral pools. Because of the abundance of water, I naively expected to see more dragonflies and damselflies. Oddly enough, the opposite is mostly true, although I am seeing an abundance of some species which were hard to find in 2022.

I'm not seeing nearly as many skimmers. In 2022, if I went out to the streams (remaining pools, really) in sunny locations, there would be skimmers perched on the tops of cattails and other tall marsh plants everywhere. In some cases, there would be a skimmer perched on the tip of almost every plant between the first and second streams.

In 2023, when I went out in the afternoon to the same location, there were almost no skimmers perched on the tips of the plants.

However, in the ephemeral pools, there are dozens of Common Green Darners (Anax junius). We had a few in 2022, but nothing like the numbers everywhere this year. In the evening, I even see Common Green Darners swooping out over the farm fields in front of the house while last year, it would be members of the Libellula genus swooping around the fields in the afternoon/evening. It was strange to see the difference. I never thought I'd say this because I saw so many last year, but I miss all the Great Blue Skimmers & Needham's Skimmers that used to be everywhere. They are still here but much harder to find.

Of course, there are some things that haven't changed. The Eastern Pondhawks, Blue Dashers, and Common Whitetails are still ubiquitous.

But in the swamp, where there is now plenty of water in the streams and a growing population of both fish and crayfish, there are few Furtive Forktails to be found. Last year, I couldn't walk along a stream without seeing at least a dozen of them.

However, this year, we have more spreadwings, including Southern Spreadwings (Lestes australis), which were much harder to find and frankly, I didn't find any on our property last year. But I find them quite frequently this year.

So I'm wondering if drought conditions actually create more opportunities for Odonata to exploit whatever water still remains, due to the lower incidence of other species which might predate the nymphs or even adults. (I'm thinking of fish, amphibians, and crayfish.) The lack of fish, amphibians, and crayfish also impacts the number of wading birds (and even owls since they eat crayfish here). Perhaps the lack of waders is also beneficial to larger Odonata, such as members of the Libellula genus.

Conclusion: It will be interesting to see what conditions we have next year (2024) and how that affects the number and variety of Odonata species in Bladen County.

Posted on September 26, 2023 06:13 PM by amypadgett amypadgett | 0 comments | Leave a comment

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