Wednesday, October 10, 2012

Tiger Spiketails at Trout Brook Valley

My favorite find of the 2012 dragonfly and damselfly season was the Tiger Spiketails (Cordulegaster erronea) that I discovered at the Aspetuck Land Trust's Trout Brook Valley Conservation Area. I have mentioned and shared some of the previous odonates discovered on the property in this entry as well as this entry. I also found Delta-spotted Spiketail, Twin-spotted Spiketail, and Arrowhead Spiketail at Trout Brook Valley over the course of the season, meaning all four of the spiketail species that can be found in Connecticut were confirmed as breeding on the property.

The below photos are of a male I captured (and subsequently released unharmed where he was netted) while he was on patrol then briefly took to a nearby clearing to examine and photograph. Look at this stunning insect!

Although I discovered the species on the site in June, I purposefully held back this find because of its significance as the Tiger Spiketail is listed as "Threatened" on The Connecticut Endangered Species Act. This is defined by the Act as, "any native species documented by biological research and inventory to be likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range within the state and to have no more than nine occurrences in the state," which is obviously the absolute definition of a conservation priority species. I did not want to call attention to its location in case a well-versed collector stumbled across this entry, and I also wanted to ensure the heavily-trafficked area where it was found did not see an even greater increase in activity. While I will not share the precise spot, those who know Trout Brook Valley well will be able to deduce where the prime habitat is.

Most spiketails utilize forest streams for breeding, with males flying routes back and forth along the waterway, checking for females and rivals at all times. There are often nearby clearings for feeding. The variety of streams and associated vegetation in Trout Brook Valley lends itself to a diversity of species. I discovered the perfect habitat favored by the Tiger Spiketail, "[s]mall forest streams and seeps, often with skunk cabbage and interrupted fern", (Paulson, Dennis - Dragonflies and Damselflies of the East) in a main section of the preserve. The stream in question is actually split by a trail, but the Tigers seem to have no trouble flying over it and continuing up and down the water as it passes underneath the path.

Here is a photo of the section of the stream where I observed repeated and continual activity during the summer, complete with skunk cabbage and fern.

However, the Tigers utilized hundreds of feet of this one stream, and the entire waterway and surrounding area is very important habitat. I noted multiple males on occasion, one spotting the other followed by a fast fight in flight through the woodlands. Females were only occasionally seen, as is typical in many dragonflies, with males monitoring breeding locations continuously and females only visiting them when they are ready to breed.

My hope is that we will be able to ensure the continued increased protection of this vital patch, including the stream, surrounding vegetation, nearby clearings, and so forth, limiting activity as much as possible near the site. Even keeping people, dogs, bikes, horses, vehicles, and all traffic on the intersecting trail itself and not straying off it would help a great deal. Mammals and birds, along with woody vegetation like trees, often seem to be the primary focus of public education, conservation, and advocacy. Other species like the Tiger Spiketail and Jefferson's Salamander (see this entry for it in Trout Brook Valley) are just as important even though they are much harder to detect and may not be seen by the causal visitor, and their preservation is of the highest priority in Connecticut with its unique wetlands, waterways, and vernal pool habitats.

Scott Kruitbosch
Conservation Technician
Photos © Scott Kruitbosch and not to be reproduced without explicit permission

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