Most migrating birds must replenish energy reserves during migration. Food availability significantly influences migratory routes and can even force migrants to detour, but still little is known about potential co-migration between insectivorous birds and their insect prey. To address this gap, we focused on day-flying insects and the insectivorous birds migrating through the Červenohorské sedlo mountain pass, Czech Republic. During four seasons of insect and bird trapping, using Malaise trap and mist-nets, respectively, we recorded 23 094 birds of 80 species and 35 087 migrating hoverflies (Syrphidae) of 47 species. We found a strong temporal correlation between the number of migrating hoverflies and insectivorous birds crossing the mountain pass. The observed pattern suggests that a similar phenomenon may occur in lowlands, where both groups stop over before and after crossing the mountains. These stopovers may provide migratory birds with abundant and reliable food resources. We also found that hoverflies comprised 88% of the biomass of all trapped insects, making them the most abundant potential prey of migrating birds. Our results outline the co-migration of birds and hoverflies and shed light on possible predator-prey dynamics during migration.

Department of Ecology Faculty of Environmental Sciences Czech University of Life Sciences Prague Kamýcká 129 Prague 16500 Czechia

Department of Zoology Faculty of Science Charles University Viničná 7 Prague 2 12800 Czechia

Institute for Advanced Study Technical University of Munich Lichtenbergstraße 2a 85748 Garching Germany

TUM School of Life Sciences Ecoclimatology Technical University of Munich Hans Carl von Carlowitz Platz 2 85354 Freising Germany

Zobrazit více v PubMed

Lundmark C. 2010. Long-distance insect migration. BioScience 60 , 400–400. (10.1525/bio.2010.60.5.15) DOI

Dokter AM, Farnsworth A, Fink D, Ruiz-Gutierrez V, Hochachka WM, La Sorte FA, Robinson OJ, Rosenberg KV, Kelling S. 2018. Seasonal abundance and survival of North America’s migratory avifauna determined by weather radar. Nat. Ecol. Evol. 2 , 1603–1609. (10.1038/s41559-018-0666-4) PubMed DOI

Van Doren BM, Horton KG. 2018. A continental system for forecasting bird migration. Science 361 , 1115–1118. (10.1126/science.aat7526) PubMed DOI

Wright RM, et al. . 2022. First direct evidence of adult European eels migrating to their breeding place in the Sargasso Sea. Sci. Rep. 12 , 15362. (10.1038/s41598-022-19248-8) PubMed DOI PMC

Williams CB. 1957. Insect migration. Annu. Rev. Entomol. 2 , 163–180. (10.1146/annurev.en.02.010157.001115) DOI

Dingle H, Drake VA. 2007. What is migration? BioScience 57 , 113–121. (10.1641/b570206) DOI

Aralimarad P, Reynolds AM, Lim KS, Reynolds DR, Chapman JW. 2011. Flight altitude selection increases orientation performance in high-flying nocturnal insect migrants. Anim. Behav. 82 , 1221–1225. (10.1016/j.anbehav.2011.09.013) DOI

Bell JR, Aralimarad P, Lim KS, Chapman JW. 2013. Predicting insect migration density and speed in the daytime convective boundary layer. PLoS ONE 8 , e54202. (10.1371/journal.pone.0054202) PubMed DOI PMC

Cohen EB, Satterfield DA. 2020. Chancing on a spectacle: co‐occurring animal migrations and interspecific interactions. Ecography 43 , 1657–1671. (10.1111/ecog.04958) DOI

Furey NB, Armstrong JB, Beauchamp DA, Hinch SG. 2018. Migratory coupling between predators and prey. Nat. Ecol. Evol. 2 , 1846–1853. (10.1038/s41559-018-0711-3) PubMed DOI

Hawkes WL, Davies K, Weston S, Moyes K, Chapman JW, Wotton KR. 2023. Bat activity correlated with migratory insect bioflows in the Pyrenees. R. Soc. Open Sci. 10 , 230151. (10.1098/rsos.230151) PubMed DOI PMC

La Sorte FA, Fink D, Hochachka WM, DeLong JP, Kelling S. 2014. Spring phenology of ecological productivity contributes to the use of looped migration strategies by birds. Proc. R. Soc. B 281 , 20140984. (10.1098/rspb.2014.0984) PubMed DOI PMC

Thorup K, et al. . 2017. Resource tracking within and across continents in long-distance bird migrants. Sci. Adv. 3 , e1601360. (10.1126/sciadv.1601360) PubMed DOI PMC

Hadjikyriakou TG, Nwankwo EC, Virani MZ, Kirschel ANG. 2020. Habitat availability influences migration speed, refueling patterns and seasonal flyways of a fly-and-forage migrant. Mov. Ecol. 8 , 10. (10.1186/s40462-020-0190-4) PubMed DOI PMC

Schaub M, Jenni L. 2000. Fuel deposition of three passerine bird species along the migration route. Oecologia 122 , 306–317. (10.1007/s004420050036) PubMed DOI

Vincze O, Vágási CI, Pap PL, Palmer C, Møller AP. 2019. Wing morphology, flight type and migration distance predict accumulated fuel load in birds. J. Exp. Biol. 222 , b183517. (10.1242/jeb.183517) PubMed DOI

Briedis M, et al. . 2020. Broad‐scale patterns of the Afro‐Palaearctic landbird migration. Glob. Ecol. Biogeogr. 29 , 722–735. (10.1111/geb.13063) DOI

Alerstam T, Lindström Å. 1990. Optimal bird migration: the relative importance of time, energy, and safety. In Bird migration (ed. Gwinner E), pp. 331–351. Berlin, Germany: Springer. (10.1007/978-3-642-74542-3_22) DOI

Alerstam T. 2011. Optimal bird migration revisited. J. Ornithol. 152 , 5–23. (10.1007/s10336-011-0694-1) DOI

Schmaljohann H, Eikenaar C, Sapir N. 2022. Understanding the ecological and evolutionary function of stopover in migrating birds. Biol. Rev. 97 , 1231–1252. (10.1111/brv.12839) PubMed DOI

Wang X, Ma H, Wu Q, Zhou Y, Zhou L, Xiu X, Zhao Y, Wu K. 2023. Comigration and interactions between two species of rice planthopper (Laodelphax striatellus and Sogatella furcifera) and natural enemies in eastern Asia. Pest Manag. Sci. 79 , 4066–4077. (10.1002/ps.7603) PubMed DOI

Strandberg R, Alerstam T. 2007. The strategy of fly-and-forage migration, illustrated for the osprey (Pandion haliaetus). Behav. Ecol. Sociobiol. 61 , 1865–1875. (10.1007/s00265-007-0426-y) DOI

Imlay TL, Saldanha S, Taylor PD. 2020. The fall migratory movements of bank swallows, Riparia riparia: fly-and-forage migration? Avian Conserv. Ecol 15 , 2. (10.5751/ace-01463-150102) DOI

Wotton KR, Gao B, Menz MHM, Morris RKA, Ball SG, Lim KS, Reynolds DR, Hu G, Chapman JW. 2019. Mass seasonal migrations of hoverflies provide extensive pollination and crop protection services. Curr. Biol. 29 , 2167–2173.(10.1016/j.cub.2019.05.036) PubMed DOI

Hawkes WLS, et al. . 2022. Huge spring migrations of insects from the Middle East to Europe: quantifying the migratory assemblage and ecosystem services. Ecography 2022 , e06288. (10.1111/ecog.06288) DOI

Gilbert F. 2019. Migration: ecosystem services helicoptered in. Curr. Biol. 29 , R697–R699. (10.1016/j.cub.2019.06.013) PubMed DOI

Doyle T, Hawkes WLS, Massy R, Powney GD, Menz MHM, Wotton KR. 2020. Pollination by hoverflies in the Anthropocene. Proc. R. Soc. B 287 , 20200508. (10.1098/rspb.2020.0508) PubMed DOI PMC

Cuthill I, Bennett A. 1993. Mimicry and the eye of the beholder. Proc. R. Soc. B 253 , 203–204. (10.1098/rspb.1993.0103) DOI

Golding Y, Edmunds M. 2000. Behavioural mimicry of honeybees (Apis mellifera) by droneflies (Diptera: Syrphidae: Eristalis spp.). Proc. R. Soc. Lond. B 267 , 903–909. (10.1098/rspb.2000.1088) PubMed DOI PMC

Hlaváček A, Daňková K, Benda D, Bogusch P, Hadrava J. 2022. Batesian-Müllerian mimicry ring around the oriental hornet (Vespa orientalis). J. Hymenopt. Res. 92 , 211–228. (10.3897/jhr.92.81380) DOI

Grim T. 2006. An exceptionally high diversity of hoverflies (Syrphidae) in the food of the reed warbler (Acrocephalus scirpaceus). Biologia 61 , 235–239. (10.2478/s11756-006-0036-6) DOI

Wiesenborn WD, Heydon SL. 2007. Diets of breeding southwestern willow flycatchers in different habitats. Wilson J. Ornithol. 119 , 547–557. (10.1676/06-101.1) DOI

Bryant DM. 1973. The factors influencing the selection of food by the house martin (Delichon urbica (L.)). J. Anim. Ecol. 42 , 539. (10.2307/3123) DOI

Krištín A. 1991. Feeding of some polyphagous songbirds on Syrphidae, Coccinellidae and aphids in beech–oak forests. In Behavioural and impact of aphidophaga (eds Dixon R, Hodek A), pp. 183–186. Hague, The Netherlands: Academic Publishing.

Hlaváček A, Lučan RK, Hadrava J. 2022. Autumnal migration patterns of hoverflies (Diptera: Syrphidae): interannual variability in timing and sex ratio. PeerJ 10 , e14393. (10.7717/peerj.14393) PubMed DOI PMC

Vavřík M, Zicha F, Belfín O, Koukolíková A, Lučan R, Lučan K. 2016. Podzimní tah ptáků přes Červenohorské sedlo. Autumn bird migration over the Červenohorské sedlo mountain pass. Zprávy MOS 74 , 4–73.

Hallmann CA, et al. . 2017. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLoS ONE 12 , e0185809. (10.1371/journal.pone.0185809) PubMed DOI PMC

Bot S, Van de Meutter F. 2023. Hoverflies of Britain and north-west Europe: a photographic guide, 1st edn. London, UK: Bloomsbury Publishing.

Hippa H, Nielsen T, van Steenis J. 2001. The West Palaearctic species of the genus Eristalis latreille (Diptera, Syrphidae). Nor. J. Entomol. 48 , 289–327.

Láska P, Mazánek L, Bičík V. 2013. Key to adults and larvae of the genera of European Syrphinae (Diptera, Syrphidae). Slez. Sborník 62 , 193–206. (10.2478/cszma-2013-0021) DOI

Busse P, Meissner W. 2015. Bird ringing station manual. Berlin, Germany: De Gruyter. (10.2478/9788376560533) DOI

Venables WN, Ripley BD. 2002. Modern applied statistics with S. New York, NY: Springer. (10.1007/978-0-387-21706-2) DOI

Fox J, et al. . 2023. car: companion to applied regression. See https://r-forge.r-project.org/projects/car/, https://CRAN.R-project.org/package=car, https://www.john-fox.ca/Companion/index.html.

Neter J, Kutner M, Nachtsheim C, Wasserman W. 2005. Applied linear statistical models, 5th edn. Boston, MA: McGraw-Hill Irwin.

Lüdecke D, Ben-Shachar M, Patil I, Waggoner P, Makowski D. 2021. performance: an R package for assessment, comparison and testing of statistical models. J. Open Source Softw. 6 , 3139. (10.21105/joss.03139) DOI

Storchová L, Hořák D. 2018. Life‐history characteristics of European birds. Glob. Ecol. Biogeogr. 27 , 400–406. (10.1111/geb.12709) DOI

Hawkes WL, Menz MHM, Wotton KR. 2024. Lords of the flies: dipteran migrants are diverse, abundant and ecologically important. bioRxiv. (10.1101/2024.03.04.583324) PubMed DOI

Eimer T. 1882. Über eine Wanderun von Dipteren und Libellen. Entomol Ztg Stettin 260.

Beebe W. 1951. Migration of insects (other than Lepidoptera) through Portachuelo Pass, Rancho Grande, north-central Venezuela. Zoologica 36 , 255–266. (10.5962/p.203488) DOI

Lack E. 1951. Migration of insects and birds through a Pyrenean oass. J. Anim. Ecol. 20 , 63. (10.2307/1644) DOI

Schmaljohann H, Liechti F, Bruderer B. 2007. Songbird migration across the Sahara: the non-stop hypothesis rejected! Proc. R. Soc. B 274 , 735–739. (10.1098/rspb.2006.0011) PubMed DOI PMC

Odermatt J, Frommen JG, Menz MHM. 2017. Consistent behavioural differences between migratory and resident hoverflies. Anim. Behav. 127 , 187–195. (10.1016/j.anbehav.2017.03.015) DOI

Hawkes WL, et al. . 2024. The most remarkable migrants—systematic analysis of the Western European insect flyway at a Pyrenean mountain pass. Proc. R. Soc. B 291 , 20232831. (10.1098/rspb.2023.2831) PubMed DOI PMC

Hallmann CA, Ssymank A, Sorg M, de Kroon H, Jongejans E. 2021. Insect biomass decline scaled to species diversity: general patterns derived from a hoverfly community. Proc. Natl Acad. Sci. USA 118 , e2002554117. (10.1073/pnas.2002554117) PubMed DOI PMC

Aubert J, Tiefenaou P. 1976. Douze ans de captures systematiques de Syrphides (Diptères) au col de Bretolet (Alpes valaisannes).

Aubert J, Jaccard M. 1981. Migration of hover flies (Syrphidae, Diptera) in the Jura Vaudois area. Mitteilungen Schweiz Entomol. Ges. Bull. Soc. Entomol. Suisse.

Gatter W. 1976. Der Zug der Schwebfliegen nach planmäßigen Fängen am Randecker Maar (Schwäbische Alb) (Dip. Syrphidae). Atalanta 7 , 4–18.

Gatter W, Schmid U. 1990. The migration of hoverflies at Randecker Maar. Spixiana 1–100.

Vujić A, et al. . 2023. Pollinators on the edge: our European hoverflies: the European Red List of hoverflies. Brussels, Belgium: Publications Office of the European Union.

Nisbet ICT, Drury WH. 1968. Short-term effects of weather on bird migration: a field study using multivariate statistics. Anim. Behav. 16 , 496–530. (10.1016/0003-3472(68)90046-8) DOI

Haest B, Hüppop O, van de Pol M, Bairlein F. 2019. Autumn bird migration phenology: a potpourri of wind, precipitation and temperature effects. Glob. Chang. Biol. 25 , 4064–4080. (10.1111/gcb.14746) PubMed DOI

Chapman BB, Brönmark C, Nilsson J, Hansson L. 2011. The ecology and evolution of partial migration. Oikos 120 , 1764–1775. (10.1111/j.1600-0706.2011.20131.x) DOI

Gao B, Wotton KR, Hawkes WLS, Menz MHM, Reynolds DR, Zhai BP, Hu G, Chapman JW. 2020. Adaptive strategies of high-flying migratory hoverflies in response to wind currents. Proc. R. Soc. B 287 , 20200406. (10.1098/rspb.2020.0406) PubMed DOI PMC

Malaise R. 1937. A new insect-trap. Entomol. Tidskr. 58 , 148–160.

Matthews RW, Matthews JR. 2017. The Malaise trap: its utility and potential for sampling insect populations. Great Lakes Entomol. 4 , 4. (10.22543/0090-0222.1158) DOI

Burgio G, Sommaggio D. 2007. Syrphids as landscape bioindicators in Italian agroecosystems. Agric. Ecosyst. Environ. 120 , 416–422. (10.1016/j.agee.2006.10.021) DOI

Campbell JW, Hanula JL. 2007. Efficiency of Malaise traps and colored pan traps for collecting flower visiting insects from three forested ecosystems. J. Insect Conserv. 11 , 399–408. (10.1007/s10841-006-9055-4) DOI

Brattström O, Shapoval A, Wassenaar LI, Hobson KA, Åkesson S. 2018. Geographic origin and migration phenology of European red admirals (Vanessa atalanta) as revealed by stable isotopes. Mov. Ecol. 6 , 25. (10.1186/s40462-018-0143-3) PubMed DOI PMC

Knoblauch A, Thoma M, Menz MHM. 2021. Autumn southward migration of dragonflies along the Baltic coast and the influence of weather on flight behaviour. Anim. Behav. 176 , 99–109. (10.1016/j.anbehav.2021.04.003) DOI

Barta Z, McNamara JM, Houston AI, Weber TP, Hedenström A, Feró O. 2008. Optimal moult strategies in migratory birds. Phil. Trans. R. Soc. B 363 , 211–229. (10.1098/rstb.2007.2136) PubMed DOI PMC

Marra PP, Francis CM, Mulvihill RS, Moore FR. 2005. The influence of climate on the timing and rate of spring bird migration. Oecologia 142 , 307–315. (10.1007/s00442-004-1725-x) PubMed DOI

Kumar V, Wingfield JC, Dawson A, Ramenofsky M, Rani S, Bartell P. 2010. Biological clocks and regulation of seasonal reproduction and migration in birds. Physiol. Biochem. Zool. 83 , 827–835. (10.1086/652243) PubMed DOI

Reynolds SK, Clem CS, Fitz‐Gerald B, Young AD. 2024. A comprehensive review of long‐distance hover fly migration (Diptera: Syrphidae). Ecol. Entomol. 49 , 749–767. (10.1111/een.13373) DOI

Massy R, Hawkes WLS, Doyle T, Troscianko J, Menz MHM, Roberts NW, Chapman JW, Wotton KR. 2021. Hoverflies use a time-compensated sun compass to orientate during autumn migration. Proc. R. Soc. B 288 , 20211805. (10.1098/rspb.2021.1805) PubMed DOI PMC

Schaub M, Jenni L. 1999. Does tape-luring of migrating Eurasian reed-warblers increase number of recruits or capture probability? Auk 116 , 1047–1053. (10.2307/4089684) DOI

Wojczulanis-Jakubas K, Wietrzykowski J, Jakubas D. 2016. Response of reed warbler and sedge warbler to acoustic playback in relation to age, sex, and body condition. J. Ornithol. 157 , 137–143. (10.1007/s10336-015-1260-z) DOI

Hlaváček A, Mikula P, Hadrava J, Lucan R. 2025. Supplementary material from: Migrating hoverflies as potential food source for co-migrating insectivorous birds. FigShare (10.6084/m9.figshare.c.7687065) PubMed DOI PMC

Migrating hoverflies as potential food source for co-migrating insectivorous birds

Zobrazit více v PubMed

figshare
10.6084/m9.figshare.c.7687065