N21 2019 Northeastern Naturalist Notes Vol. 26, No. 3 A.C. Kennedy, H.B. White III , and D.W. Tallamy Predation of Dragonfly Nymphs by Passerines Ashley C. Kennedy1,*, Harold B. White III2, and Douglas W. Tallamy1 Abstract - Avian predation of dragonflies and damselflies (Odonata) is fairly well-documented, but most observations are restricted to non-passerine birds eating adult odonates. As nymphal odonates are aquatic, most passerine birds would not encounter them while foraging but instead are more likely to catch teneral adults on their maiden flights. Photographs taken by naturalists over the past several years suggest that passerine predation on odonate nymphs, while apparently rare, occurs across a wider range of species than previously documented. Introduction. In general, observations of passerine predation of odonates are uncommon compared to those of other insect groups, and observations of passerine predation of odonate nymphs are even rarer. Among the few passerine species known to forage heavily on dragonflies are Progne subis (L.) (Purple Martin; Beal 1918, Johnston 1967), Sayornis nigricans (Swainson) (Black Phoebe; Freehling and Johnson 2018, Ohlendorf 1976), Tyrannus tyrannus L. (Eastern Kingbird; Gallucci and Freeman 2007), Riparia riparia L. (Bank Swallow; Kennedy 1950), Xanthocephalus xanthocephalus (Bonaparte) (Yellow-headed Blackbird; Kennedy 1950), and Cistothorus palustris A. Wilson (Marsh Wren; Kennedy 1950), but these species overwhelmingly prey on adults. Odonate nymphs typically spend most of their lives in the water, where most upland passerine birds would not encounter them. They are out of the water only a few hours at most before they eclose as adults; thus, the encounter window is short. It is the weak-flying teneral adults on their maiden flight that are most often the target of hungry passerines. Corbet (1999) noted that herons and grebes are among the major avian predators of odonate nymphs, and commented that predation on nymphs tends to be “brief and episodic.” By far, the most extensive compilation of records on bird–odonate interactions is that of Kennedy (1950), who tabulated the data from the stomach contents of over 61,000 birds representing 494 species. Of those specimens, dragonfly remains were present in some stomachs of 184 species. Kennedy found that nearly all the bird species that preyed upon odonate nymphs were non-passerines (e.g., grebes, herons, ducks, gulls, and kingfishers); the major exception to this rule was Turdus migratorius propinquus Ridgway (Western Robin [a subspecies of American Robin]), which he observed “hanging about the water and catching dragonflies as they emerge in numbers” (Kennedy 1950:127). Recently, a wide-scale community-science project has garnered photographic contributions of birds with insect prey from naturalists across North America. A subset of these photographs that show odonate nymphs as prey items suggest that passerine predation on odonate nymphs is more widespread than previously known. Methods. In 2014, to develop a better understanding of bird food webs, A.C. Kennedy and D.W. Tallamy launched a community-science project to crowd-source photographs of birds eating insects and other arthropods. The project was advertised through social and print media (e.g., www.facebook.com/WhatDoBirdsEat) to recruit participants from across North America. Most participants were not trained scientists, but rather, were naturalists and/or bird enthusiasts who spent a substantial amount of time in the field. A.C. 1University of Delaware, Department of Entomology and Wildlife Ecology, Newark, DE 19716. 2University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19716. *Corresponding author: kennedya@udel.edu. Manuscript Editor: Jean-Pierre Savard Notes of the Northeastern Naturalist, Issue 26/3, 2019 2019 Northeastern Naturalist Notes Vol. 26, No. 3 N22 A.C. Kennedy, H.B. White III , and D.W. Tallamy Kennedy also used camera traps stationed at Sialia sialis L. (Eastern Bluebird) nest boxes at the Mt. Cuba Center (Hockessin, New Castle County, DE) to capture images of adult bluebirds provisioning their nestlings with prey. Each camera trap consisted of a GoPro Hero 3+® camera (GoPro, San Mateo, CA) mounted towards the back of the nest-box roof and set for a 1-sec time-lapse. Although these were not camera traps in the traditional sense (i.e., they were not motion-activated), they served the purpose well, as they were waterproof, resistant to hot summer temperatures, small enough to be unobtrusive to the bluebirds, and successfully captured many feeding events with photos clear enough to allow for family-, genus- or species-level identification of prey. H.B. White identified odonate prey from both of these projects. Results and discussion. Of more than 6000 photographs submitted online from across North America, ~87% were clear enough to allow identification of prey to the ordinal level or below. Birds with odonate prey were depicted in 348 photographs, representing 89 bird species. Based on the time of year when the photographs were taken, we assumed that the majority of images, especially those of passerine species, depicted breeding birds who were catching insects to provision their young. The most commonly observed predators included Agelaius phoniceus (L.) (Red-winged Blackbird), accounting for 12% of images with odonate prey, followed by Purple Martins, Tachycineta bicolor (Vieillot) (Tree Swallow), Eastern Kingbirds, Yellow-headed Blackbirds, Butorides virescens (L.) (Green Heron), Sayornis phoebe (Latham) (Eastern Phoebe), Prothonotaria citrea (Boddaert) (Prothonotary Warbler), Black Phoebes, and Falco sparverius L. (American Kestrel). Six photographs revealed odonate-nymph prey items, with 4 different bird species documented as predators. Of these 4 species, 3 were passerines, and the other, Leuconotopicus borealis Vieillot (Red-cockaded Woodpecker), was not previously known to prey on odonate nymphs. From more than 8000 prey items recorded by camera traps at Eastern Bluebird nest boxes, ~93% were identified to ordinal level or below; 6 were odonates, including both adults and nymphs. Eastern Bluebirds were not previously known to be predators of dragonfly nymphs. We list below the 5 avian species observed feeding on odonate nymphs through the community science and field project endeavors described above. Order Piciformes: Red-cockaded Woodpecker: A Red-cockaded Woodpecker in Brooksville, Hernando County, FL, was photographed on 4 May 2012 bringing an odonate nymph (Libellulidae) to its nest cavity. Hanula and Franzreb (1995) provided a comprehensive list of prey brought to Red-cockaded Woodpecker nest cavities in Aiken County, SC, but did not report Odonata among the 28 arthropod taxa observed. Order Passeriformes: Geothlypis trichas (L.) (Common Yellowthroat): A Common Yellowthroat in Grand Bend, Lambton County, ON, Canada, was photographed on 23 June 2015, carrying multiple prey items in its bill (Fig. 1); these included 1 spider (female Tetragnatha sp.), 1 adult teneral damselfly (Coenagrionidae), and 1 dragonfly nymph (Libellulidae). Kennedy (1950:131) reported finding 1 dragonfly nymph within 125 examined Common Yellowthroat stomachs, and noted that these birds are “partial to thickets along streams”, explaining how they would come into contact with immature odonates. Pitangus sulphuratus (L.) (Great Kiskadee): A Great Kiskadee was photographed feeding on a dragonfly nymph (Aeshnidae) on 3 January 2016, in the Rio Grande Valley area, TX N23 2019 Northeastern Naturalist Notes Vol. 26, No. 3 A.C. Kennedy, H.B. White III , and D.W. Tallamy Figure 1. Common Ye l l o w t h r o a t i n Grand Bend, Lambton County, ON, Canada; June 2015. Photograph © Ron Goodridge. Figure 2. Great Kiskadee in Rio Grande Valley area, TX; January 2016. Photograph © Thomas Dunkerton. 2019 Northeastern Naturalist Notes Vol. 26, No. 3 N24 A.C. Kennedy, H.B. White III , and D.W. Tallamy F igure 3. Red-w inged Blackbird in Conyers, Rockdale County, GA; June 2018. Photograph © Becky Cover. Figure 4. Eastern Bluebird in Hockessin, New Castle County, DE; July 2017. Photograph © Ashley Kennedy. N25 2019 Northeastern Naturalist Notes Vol. 26, No. 3 A.C. Kennedy, H.B. White III , and D.W. Tallamy (Fig. 2). This species is known to have a catholic diet; Munin et al. (2012:462) reported that Great Kiskadees feed on both adult dragonflies and aquatic insects, and noted that predation on dragonflies “does not seem to be advantageous, as it required long searching time”. Gorena (1997) reported that dragonflies were the most common insect prey of Great Kiskadees in Texas, but did not indicate if this grouping includes nymphs. Red-winged Blackbird: A female Red-winged Blackbird in Sorel, QC, Canada, was photographed on 10 May 2010 with a dragonfly nymph (Libellulidae). A photographer in Oakdale, MN, photographed a female Red-winged Blackbird preying on a dragonfly nymph (Corduliidae: Epitheca sp.) on 22 May 2016. On 25 June 2018, a female Red-winged Blackbird was photographed with 2 prey items in its bill—a spider (Dolomedes triton Walckenaer) and a dragonfly nymph—in Conyers, Rockdale County, GA (Fig. 3). Kennedy (1950) reported finding dragonflies in 30 of 1000 examined Red-winged Blackbird stomachs, with nymphs in 8 of them. Eastern Bluebird: On 25 July 2017, camera traps photographed 2 Eastern Bluebird females in Hockessin, New Castle County, DE, returning to their nests with dragonfly nymphs (Aeshnidae: Epiaeschna heros [Fabricius]). Each female predated 2 nymphs for a total of 4 immature odonate prey. The first female (Fig. 4) caught the 2 nymphs 8 min apart; the second captured her prey 22 min apart. These 4 items were the only odonate nymph prey observed in more than 8000 total recorded prey items of Eastern Bluebirds at this site. This study also documented an additional 6 adult odonate prey items (including 2 clubtails; Gomphidae: Dromogomphus spinosus Selys). Kennedy (1950) reported finding adult dragonflies in 4 of 855 examined Eastern Bluebird stomachs, but did not report nymphs. Conclusion. As previous authors (e.g., Corbet 1999, Kennedy 1950) have reported, our data indicate that it is unlikely that any North American passerines specialize in preying on odonate nymphs. Immature odonates are aquatic; thus, they only leave the water immediately prior to emergence, which often occurs over a very short period of mass emergence. Many birds will opportunistically forage on available prey, such as odonate nymphs, that are briefly present in large numbers on emergent vegetation or shorelines. The observations recorded here lend additional support to the breadth in variety and plasticity of passerine birds’ diets. It is likely that passerines consume few, if any, immature odonates; in contrast, we documented 89 bird species preying on adult odonates. This finding has implications for conservation and land management, as it indicates that wetland habitats are useful for a large number of bird species. Acknowledgments. We are indebted to the photographers who contributed their images to this effort: Roxie Aho, Barbara Bowen, Becky Cover, Thomas Dunkerton, Ron Goodridge, and Gilles Papillon. We also thank the Mt. Cuba Center for use of their beautiful site and Daniel Hildreth for his generous support. Literature Cited Beal, F.E.L. 1918. Food habits of the swallows: A family of valuable native birds. US Department of Agriculture Bulletin 619:1–28. Corbet, P.S. 1999. Dragonflies: Behavior and Ecology of Odonata. Cornell University Press, Ithaca, NY. 864 pp. Freehling, M., and K. Johnson. 2018. Black Phoebe (Sayornis nigricans) predation on Variegated Meadowhawk (Sympetrum corruptum). Argia 30(3):17–18. Gallucci, T., and B. Freeman. 2007. Notes on avian predators of Odonata. Argia 19(2):21–23. Gorena, R.L. 1997. Notes on the feeding habits and prey of adult Great Kiskadees. Bulletin of the Texas Ornithological Society 30(1):18–19. 2019 Northeastern Naturalist Notes Vol. 26, No. 3 N26 A.C. Kennedy, H.B. White III , and D.W. Tallamy Hanula, J.L., and K.E. Franzreb. 1995. Arthropod prey of nestling Red-cockaded Woodpeckers in the Upper Coastal Plain of South Carolina. The Wilson Bulletin 107(3):485–495. Johnston, R.F. 1967. Seasonal variation in the food of the Purple Martin, Progne subis, in Kansas. Ibis 109:8–13. Kennedy, C.H. 1950. The relation of American dragonfly-eating birds to their prey. Ecological Monographs 20(2):103–142. Munin, R.L., E. Fischer, and J.M. Longo. 2012. Foraging of Great Kiskadees (Pitangus sulphuratus) and food items offered to nestlings in the Pantanal. Brazilian Journal of Biolog y 72(3):459–462. Ohlendorf, H.M. 1976. Comparative breeding ecology of phoebes in Trans-Pecos Texas. The Wilson Bulletin 88:255–271.