Gray Petaltail

Tachopteryx thoreyi (Hagen in Selys, 1858)

Tachopteryx thoreyi
Martha Reinhardt

Insecta (Insects)
Petaluridae (Petaltails)
State Protection
Special Concern
Listed as Special Concern by New York State: at risk of becoming Threatened; not listed as Endangered or Threatened, but concern exists for its continued welfare in New York; NYS DEC may promulgate regulations as to the taking, importation, transportation, or possession as it deems necessary.
Federal Protection
Not Listed
State Conservation Status Rank
Imperiled in New York - Very vulnerable to disappearing from New York due to rarity or other factors; typically 6 to 20 populations or locations in New York, very few individuals, very restricted range, few remaining acres (or miles of stream), and/or steep declines.
Global Conservation Status Rank
Apparently Secure globally - Uncommon in the world but not rare; usually widespread, but may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors.


Did you know?

The gray petaltail is the only northeastern dragonfly species whose larvae may not be truly aquatic. The larvae live in the mud and vegetation of mucky, mossy, spring seeps which often contain very little standing water (Needham et al. 2000, Nikula et al. 2003).

State Ranking Justification

As of 2023, there are 16 confirmed locations for this uncommon and local species located in just 9 counties including: Cattaraugus, Chautauqua, Lewis, Livingston, Wyoming, Putnam, Rockland, Schuyler, Steuben, and Tompkins. Three additional locations are considered historic. Several of the sites are in close proximity to one another and could be functioning as a single metapopulation. While additional, undiscovered populations are expected, the specific nature of the species' habitat suggests that the number of sites may not be large. Although most known populations are on protected lands (12 of 16 occurrences), populations for this species are not thought to be particularly large and there are significant potential threats to the species.

Short-term Trends

There is no information on population trends for this species at known locations. One previously new population was detected in 2021 in the Hudson Highlands Ecozone on state park property. However, three known occurrences were surveyed between 2018-2023 and while habitat appeared suitable this species was not detected. There is the possibility that some sites have been lost in recent years due to new suburban and other development. A fourth known occurrence in Cattaraugus County was also surveyed in 2023 and was previously known as a site where Gray Petaltail dragonflies were reliably observed. It appears that there has been ongoing habitat degradation and the site may not be suitable due to changes in hydrology, sedimentation, and encroachment of Phragmites all impacting the fen. Over a decade ago, 6-7 individuals were seen, however recent surveys in 2018 and 2021 observed just a single individual, and zero individuals were seen in 2023.

Long-term Trends

Several sites have been known for decades indicating that they are viable and presumably stable over the long-term. Suburban and other development has been taking place in the lower Hudson Valley portion of the species range for decades and it is possible that some sites, including at least two represented by historical records, have been lost.

Conservation and Management


Since seepage areas are the key larval habitat for this species, any activities that alter the quality or quantity of groundwater seepage in an occupied area would pose a threat to Gray Petaltails. The most important likely negative impacts would come from changes in natural hydrology through the building of dams, increases in sediment load of the seepage (e.g., extensive logging in or adjacent to the seepage), changes in dissolved oxygen content, direct effects of pesticides, and chemical contamination by runoff or agricultural discharge. Direct, intentional killing by people is a possible threat to this species. In at least one state park, petaltails squashed by park visitors have been observed. Petaltails are not wary and occasionally land on people whose first reaction is probably to swat the insect. In addition to potentially directly harming individuals, unaware visitors may venture off trail and degrade sensitive seep habitat threatening Gray Petaltail persistence at a site (Hietala-Henschell et al. 2022).
Invasive species may have an indirect negative impact on Gray Petaltail populations by contributing to overall forest health degradation. For example, Spongy Moth (Lymantria dispar) and Hemlock Woolly Adelgid (Adelges tsugae) have been observed in abundance at known Gray Petaltail sites (Hietala-Henschell et al. 2022). In addition to habitat degradation and destruction, dragonflies are also at risk to contamination if pesticides are needed for invasive species management. Dragonflies are especially vulnerable to environmental pollutants during emergence because their exoskeletons haven’t hardened yet making them susceptible to insecticides (Orr 2005). Orr (2005) reviewed how management targeting mosquitoes may negatively impact dragonfly populations and suggests that if a general insecticide (e.g., malathion) is used in semi-urban locations near protected areas it could extend to the riparian zones of parks or protected areas adjacent to the area of treatment. While direct studies are limited, general insecticides are not specific to their target pest, and it can be assumed that exposure to insecticide sprays could harm dragonflies by reducing fitness or causing mortality (Orr 2005).
Although much of the area occupied by this species is physically protected, it may also be degraded by the increasing threat of climate change. Increased temperatures and changes in precipitation may negatively affect seeps and fens, as these communities are sensitive to changes in water supply. A recent Climate Change Vulnerability assessment suggests that the Gray Petaltail is presumed stable in New York state and current evidence does not support a substantial change in abundance or range extent by 2050 (Schlesinger et al. 2011). However, the authors found that this species may experience decline specifically when it comes to its physiological hydrological niche, dependence of specific disturbance, and its required physical habitat (Schlesinger et al. 2011).

Conservation Strategies and Management Practices

Consideration should be given to providing information to the public at state parks where this species occurs. The tame and harmless nature of the insects could be stressed in order to reduce the likelihood of the dragonflies being killed by startled hikers. For example, a photograph and brief information sheets could be provided at kiosks located near the entrances to trails during the late May-July flight period. In addition to the signage already present, hosting nature walks, promoting the use of community science (e.g., iNaturalist), using social media, and raising awareness in general may benefit this harmless animal, especially during the adult flight period of May through July.
Decisions regarding invasive species management and pesticide applications need to take into consideration the potential impact to Gray Petaltail dragonflies during their activity periods and at sensitive locations. For example, occupied areas or other small clean-water springs and seeps on public and private land should not receive pesticide applications during the activity period, especially through June and July when adults are most active.
Management considerations could include supporting natural water flows, minimizing siltation, and minimizing soil compaction of the mucky soils in breeding habitats. Maintaining the natural vegetation regime of closed canopies, a semi-shaded microclimate, retaining high moisture levels, and ensuring a diverse herbaceous layer are important for occupied seep habitats. For stream sites, maintaining a wide forested buffer supports natural flooding cycles and depositional dynamics and might help stabilize flow and temperature regimes.
This species relies on spring seeps for larval habitat and completing its life cycle. Trail maintenance and planning can also help to protect larval habitat: avoiding new trail building in seepage areas, maintaining existing trails to reduce erosion and keep patrons on trails, and re-routing or installing bridges or boardwalks over seeps or streams (Hietala-Henschell et al. 2022). In addition to protecting individual sites, it’s imperative that habitat connectivity is maintained and restored as environments are changing due to climate change (Schlesinger et al. 2011).

Research Needs

Although the larvae are known to be associated with seepage areas, and seepage areas are very apparent at some known sites, probable larval habitat is less apparent at some others. A mark-recapture study similar to the study conducted by Dunkle (1981) in Florida would provide the basis for a better overall population estimate and long-term monitoring efforts for the species.



The general habitat of the Gray Petaltail can be described as hillside seeps and fens in areas of deciduous forest (Dunkle 2000). In New York, most known populations are found at rocky gorges and glens with deciduous or mixed forests. Small shallow streams flow through the gorges and glens, and these streams are fed by hillside seepage areas, groundwater fed seepage streams or fens. In the Finger Lakes region, stable populations have been observed along streams that run through rocky gorges; these areas typically have dappled light, are surrounded by seeps and small spring habitats, and are bordered by mixed deciduous and hemlock forest (Hietala-Henschell et al. 2022). Recent detections of previously unknown populations in the Hudson Highlands were observed in habitats similar to the general habitat description, suggesting this species is not limited to gorge specific habitats in New York. All New York sites occurred in or near seepage areas. The seepage areas represent the larval habitat for these populations, while the adults use seepage areas, stream courses, and the surrounding forest (New York Natural Heritage Program 2023).

Associated Ecological Communities

  • Appalachian oak-hickory forest (guide)
    A hardwood forest that occurs on well-drained sites, usually on ridgetops, upper slopes, or south- and west-facing slopes. The soils are usually loams or sandy loams. This is a broadly defined forest community with several regional and edaphic variants. The dominant trees include red oak, white oak, and/or black oak. Mixed with the oaks, usually at lower densities, are pignut, shagbark, and/or sweet pignut hickory.
  • Appalachian oak-pine forest (guide)
    A mixed forest that occurs on sandy soils, sandy ravines in pine barrens, or on slopes with rocky soils that are well-drained. The canopy is dominated by a mixture of oaks and pines.
  • Floodplain forest (guide)
    A hardwood forest that occurs on mineral soils on low terraces of river floodplains and river deltas. These sites are characterized by their flood regime; low areas are annually flooded in spring, and high areas are flooded irregularly.
  • Hemlock-northern hardwood forest (guide)
    A mixed forest that typically occurs on middle to lower slopes of ravines, on cool, mid-elevation slopes, and on moist, well-drained sites at the margins of swamps. Eastern hemlock is present and is often the most abundant tree in the forest.
  • Marsh headwater stream* (guide)
    The aquatic community of a small, marshy perennial brook with a very low gradient, slow flow rate, and cool to warm water that flows through a marsh, fen, or swamp where a stream system originates. These streams usually have clearly distinguished meanders (i.e., high sinuosity) and are in unconfined landscapes.
  • Oak-tulip tree forest (guide)
    A hardwood forest that occurs on moist, well-drained sites in southeastern New York. The dominant trees include a mixture of five or more of the following: red oak, tulip tree, American beech, black birch, red maple, scarlet oak, black oak, and white oak.
  • Rich sloping fen (guide)
    A small, gently sloping wetland that occurs in a shallow depression on a slope composed of calcareous glacial deposits. Sloping fens are fed by small springs or groundwater seepage. Like other rich fens, their water sources have high concentrations of minerals and high pH values, generally from 6.0 to 7.8. They often have water flowing at the surface in small channels or rivulets.
  • Rocky headwater stream (guide)
    The aquatic community of a small- to moderate-sized perennial rocky stream typically with a moderate to steep gradient, and cold water that flows over eroded bedrock, boulders, or cobbles in the area where a stream system originates.

* probable association but not confirmed.


New York State Distribution

Overall, the statewide range for this species is quite broad, with records coming from counties across the southern portion of the state including the Lower Hudson Valley, the southern portion of the Finger Lakes and the Lake Erie portion of the Great Lakes drainage. There is a reliable site record from one location on Tug Hill (Lewis County) that may represent a disjunct portion of the range for this primarily southern species.

Global Distribution

This is principally a southern species whose range extends from northern Florida west to eastern Texas and Oklahoma, and north to southern Michigan, southern New York, and southern New England (NatureServe 2012). It appears to have a spotty, restricted distribution in parts of its range (O’Brien 2012, Patten and Smith-Patten 2013). It is also considered regionally rare in the Northeast, assessed as a Watchlist species (RSGCN 2023) and ranked as R3 (i.e., Moderate Regional Vulnerability) (White et al. 2015).

Best Places to See

  • Stony Brook State Park (Steuben County)
  • Watkins Glen State Park (Schuyler County)

Identification Comments

Identifying Characteristics

Gray Petaltails are large black and gray dragonflies that are often seen perching on tree trunks and downed logs. While they resemble some of the species of mosaic darners (genus Aeshna), they are easily distinguished from them by their well-separated eyes, and the long, parallel-sided stigma on the wing. The eyes are dark brown to gray. The thorax is mainly gray, while the abdomen is gray with black markings. Adult Gray Petaltails are approximately 7.1-8.0 cm in length. Females are similar to males but have a well-developed blade-like ovipositor. The larvae can be recognized by their short, thick, and hairy 7-jointed antennae and by the quadrate form of the prementum and the strongly angulated side margins of the abdominal segments (Needham et al. 2000).

Characters Most Useful for Identification

The well-separated eyes and the long, parallel-sided stigmas on the wings are important characters for this species, although its large size and black and gray color make it difficult to confuse with any other northeastern dragonfly species.

Best Life Stage for Proper Identification

Mature adults are the best life stage for the identification of all dragonflies. While larval identification is possible, it is best done by people with a great deal of expertise in this area.


The behavior of adult Gray Petaltails is quite interesting. They frequent sunny openings at, or near, the hillside seepages where males chase one another and wait for females to enter the habitat, and where they mate and oviposit. Males also will fly up the length of large tree trunks searching for females and both sexes frequently perch on tree trunks. Adult petaltails are easy to approach, not wary of people and in fact will frequently land on people. At the same time, they are swift of flight and are difficult to follow when they do take flight (Dunkle 1981, Needham et al. 2000, Nikula et al. 2003).

Best Time to See

The majority of the New York records and observations for this early-season species are from mid-June through mid-July, although there are also records from early June and into early August (Donnelly 1999, New York Natural Heritage Program 2023).

  • Present
  • Reproducing

The time of year you would expect to find Gray Petaltail present and reproducing in New York.

Gray Petaltail Images


Gray Petaltail
Tachopteryx thoreyi (Hagen in Selys, 1858)

  • Kingdom Animalia
    • Phylum Arthropoda (Mandibulates)
      • Class Insecta (Insects)
        • Order Odonata (Dragonflies and Damselflies)
          • Family Petaluridae (Petaltails)

Additional Resources


Donnelly, T. W. 1992. The odonata of New York State. Bulletin of American Odonatology. 1(1):1-27.

Donnelly, T.W. 1999. The dragonflies and damselflies of New York. Prepared for the 1999 International Congress of Odonatology and First Symposium of the Worldwide Dragonfly Association. July 11-16, 1999. Colgate University, Hamilton, New York. 39 pp.

Dunkle, S.W. 1981. The ecology and behavior of Tachopteryx thoreyi (Hagen) (Anisoptera: Petaluridae). Odonatologica 10 (3):189-199.

Dunkle, S.W. 2000. Dragonflies through binoculars: A field guide to dragonflies of North America. Oxford University Press: 266 pp.

Hietala-Henschell, K., E. White, and J. Lundgren. 2022. Status of Tachopteryx thoreyi (Gray Petaltail) in the Finger Lakes State Parks. Unpublished document. 4 pp.

NatureServe. 2012. NatureServe Explorer: Gray Petaltail. Online Database. Available at:

Needham, J.G., M.J. Westfall, Jr., and M.L. May. 2000. Dragonflies of North America. Revised edition. Scientific Publishers, Gainesville, Florida. 939 pp.

New York Natural Heritage Program. 2006. Biotics Database. Albany, NY.

New York Natural Heritage Program. 2023. Element Occurrence Database. State University of New York College of Environmental Science and Forestry, Albany, NY.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

Nikula, B., J.L. Loose, and M.R. Burne. 2003. A field guide to the dragonflies and damselflies of Massachusetts. Division of Fisheries and Wildlife, Natural Heritage and Endangered Species Program, Westborough, MA. 197 pp.

Orr, R. 2005. Dragonflies and damselflies, significant non-target insects likely to be affected by West Nile Virus management in the National Capital Parks. National Park Service Research Project (PIMIS #76797). 42 pp.

O’Brien, M. 2012. Collecting Gray Petaltails (Odonata) with Mr. Williamson. Museum of Zoology, University of Michigan, Ann Arbor, Michigan.

Patten M. and B. Smith-Patten. 2013. Odonata species of special concern for Oklahoma, USA. International Journal of Odonatology. 16:4, 327-350, DOI: 10.1080/13887890.2013.868328.

RSGCN. 2023. Online database for Regional Species of Greatest Conservation Need. Northeast Fish and Wildlife Diversity. Available at:

Schlesinger, M.D., J.D. Corser, K.A. Perkins, and E.L. White. 2011. Vulnerability of at-risk species to climate change in New York. New York Natural Heritage Program, Albany, NY.

White, E.L., P.D. Hunt, M.D. Schlesinger, J.D. Corser, P.G. deMaynadier. 2015. Prioritizing Odonata for conservation action in the northeastern USA. Freshwater Science vol. 34.


About This Guide

This guide was authored by: Paul G. Novak and Katie G. Hietala-Henschell

Information for this guide was last updated on: December 20, 2023

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Tachopteryx thoreyi. Available from: Accessed June 23, 2024.