Peregrine falcon and merlin predation on small shorebirds and passerines in Alberta
Abstract
This study describes and compares hunting techniques and predatory efficiency of peregrine falcon (Falco peregrinus) and merlin (Falco columbarius) preying on small shorebirds and passerines in open agricultural lands around Beaverhills Lake, Alberta, during spring and fall, 1965–1987. Hunting methods were divided into four categories: (i) surprise attacks with less than six swoops at prey initially on the ground, (ii) short pursuits with less than six swoops at flying prey, (iii) persistent, long-range pursuits with more than six swoops, and (iv) other or unknown methods. They made up, respectively, 73.9, 17.2, 2.5, and 6.4% of 647 hunts by peregrines, and 72.3, 16.1, 4.5, and 7.1 % of 354 hunts by merlins. Persistent pursuits of prey were significantly more successful than surprise attacks by merlins (62.5 vs. 9.4%, P < 0.00001), but not by peregrines (18.8 vs. 8.8%, P = 0.40). I postulate that peregrines and merlins employ persistent hunting techniques only if surprise attacks are unproductive because of (i) lack of expertise of the falcon, (ii) scarcity of prey, (iii) unsuitable habitat, and (iv) effective early warning by flocking prey. Peregrines captured 50 shorebirds of 11 species, and 3 passerines of 2 species. Merlins captured 28 shorebirds of 8 species, and 16 passerines of 5 species. Adult male merlins were significantly more successful than immatures and adult females combined (38.7 vs. 9.1%, P < 0.00001). Adult peregrines were not significantly more successful than either spring or fall immatures (9.2 vs. 7.2 and 4.9%, P = 0.21, P = 0.24, respectively). Merlins were significantly more successful than peregrines in hunting small passerines (12.2 vs. 3.8%, P = 0.04), but not significantly more successful in hunting small shorebirds (12.6 vs. 8.8%, P = 0.10).
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Even when falcons are not breeding, they tend to bring most of their prey back to their perch, or even to consume their prey mid-air.
“Hence, even when falcons are not breeding, they tend to bring most of their prey back to their perch, or even to consume their prey mid-air (Dekker 1988).”
From Sexual size dimorphism, prey morphology and catch success in relation to flight mechanics in the peregrine falcon: a simulation study (2019) · cites this paper as Dekker 1988
Cites
Eagles, Hawks and Falcons of the World
Schultz, V., Brown, L., & Amadon, D. (1970) · Journal of Wildlife Management · doi:10.2307/3798890 · Cited by 681 · see citing works
Powell, G. (1974) · Animal Behaviour · doi:10.1016/s0003-3472(74)80049-7 · Cited by 522 · see citing works
Southern, H., & Ratcliffe, D. A. (1981) · Journal of Animal Ecology · doi:10.2307/4158 · Cited by 445 · see citing works
Ward, F. P., & Ratcliffe, D. A. (1981) · Journal of Wildlife Management · doi:10.2307/3808143 · Cited by 290 · see citing works
Raptor Predation on Wintering Shorebirds
Page, G. W., & Whitacre, D. F. (1975) · Ornithological Applications · doi:10.2307/1366760 · Cited by 264 · see citing works
Snyder, N. R., & Rudebeck, G. (1950) · Oikos · doi:10.2307/3564663 · Cited by 199 · see citing works
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Behavioral decisions made under the risk of predation: a review and prospectus
Lima, S. L., & Dill, L. M. (1990) · Canadian Journal of Zoology · doi:10.1139/z90-092 · Cited by 8,196 · see citing works
Western sandpipers have altered migration tactics as peregrine falcon populations have recovered
Ydenberg, R. C., Butler, R. W., Lank, D. B., Smith, B. D., & Ireland, J. (2004) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.2004.2713 · Cited by 186 · see citing works
“Merlins (Falco columbarius) and peregrines (F. peregrinus) rely on stealth and speed to capture sandpipers ( Dekker 1988, 1998 ), and hence sandpipers are especially vulnerable at migratory stopover sites, where flight performance attributes important in predator escape and evasion, such as take-off, acceleration and…”
BackgroundCresswell, W. R. (1994) · Behavioral Ecology and Sociobiology · doi:10.1007/bf00167747 · Cited by 157 · see citing works
Trade‐offs, condition dependence and stopover site selection by migrating sandpipers
Ydenberg, R. C., Butler, R. W., Lank, D. B., Guglielmo, C. G., Lemon, M. J. F., & Wolf, N. G. (2002) · Journal of Avian Biology · doi:10.1034/j.1600-048x.2002.330108.x · Cited by 149 · see citing works
“Falcons employ a variety of techniques when hunting sandpipers, but surprise substantially increases the probability of prey capture (Page and Whitacre 1975, Dekker 1988).”
BackgroundInfluentialCresswell, W. R. (1996) · Ibis · doi:10.1111/j.1474-919x.1996.tb04770.x · Cited by 140 · see citing works
Protective Cover and the Use of Space: Different Strategies in Finches
Lima, S. L. (1990) · Oikos · doi:10.2307/3545422 · Cited by 127 · see citing works
Cresswell, W. R., & Whitfield, D. P. (1994) · Ibis · doi:10.1111/j.1474-919x.1994.tb01088.x · Cited by 97 · see citing works
Lima, S. L. (1992) · Oikos · doi:10.2307/3545181 · Cited by 92 · see citing works
van den Hout, P. J., Spaans, B., & Piersma, T. (2008) · Ibis · doi:10.1111/j.1474-919x.2008.00785.x · Cited by 69 · see citing works
“Coastal shorebirds have much to fear from fast aerial predators, especially falcons (Dekker 1980, 1988, 2003, Bijlsma 1990, Buchanan 1996, Fuller et al. 1998, McGrady et al. 2002, Ydenberg et al. 2004).”
BackgroundRAPTOR PREDATION ON WINTERING DUNLINS IN RELATION TO THE TIDAL CYCLE
Dekker, D., & Ydenberg, R. C. (2004) · Ornithological Applications · doi:10.1093/condor/106.2.415 · Cited by 69 · see citing works
Self-citationExperimental evidence that migrants adjust usage at a stopover site to trade off food and danger
Pomeroy, A. C., Butler, R. W., & Ydenberg, R. C. (2006) · Behavioral Ecology · doi:10.1093/beheco/arl043 · Cited by 64 · see citing works
“Peregrine falcons (Falco peregrinus), merlins (Falco columbarius), and other raptors hunt shorebirds, including western sandpipers (Page and Whitacre 1975; Whitfield 1985; Buchanan et al. 1988; Dekker 1988; Cresswell 1994, 1996), and achieve greatest hunting success using cover to conceal their approach (Whitfield 198…”
BackgroundSprague, A. J., Hamilton, D. J., & Diamond, A. W. (2008) · Avian Conservation and Ecology · doi:10.5751/ace-00252-030204 · Cited by 50 · see citing works
“Several studies have shown that raptors hunt most successfully when using surprise attacks launched from cover (Page and Whitacre 1975, Dekker 1988, Cresswell 1996, Pomeroy 2006).”
BackgroundMIGRATION AND RANGING OF PEREGRINE FALCONS WINTERING ON THE GULF OF MEXICO COAST, TAMAULIPAS, MEXICO
McGrady, M., Maechtle, T. L., Vargas, J. J., Seegar, W. S., & Peña, M. C. P. (2002) · Ornithological Applications · doi:10.1650/0010-5422(2002)104[0039:maropf]2.0.co;2 · Cited by 45 · see citing works
Dekker, D., Dekker, I., Christie, D. A., & Ydenberg, R. C. (2011) · Waterbirds · doi:10.1675/063.034.0208 · Cited by 39 · see citing works
“Peregrines often hunt by stealth in attempts to take their prey by surprise (Dekker 1980, 1988; Cresswell 1996).”
BackgroundSelf-citationDuijns, S., Anderson, A. M., Aubry, Y., Dey, A., Flemming, S. A., Francis, C. M., Friis, C. A., Gratto‐Trevor, C. L., Hamilton, D. J., Holberton, R. L., et al. (2019) · Scientific Reports · doi:10.1038/s41598-019-45862-0 · Cited by 37 · see citing works
Feeding–Danger Trade-Offs Underlie Stopover Site Selection by Migrants
Pomeroy, A. C., Seaman, D. A. A., Butler, R. W., Elner, R. W., Williams, T. D., & Ydenberg, R. C. (2008) · Avian Conservation and Ecology · doi:10.5751/ace-00240-030107 · Cited by 32 · see citing works
“…(F. columbarius), and other raptors hunt shorebirds, including Western Sandpipers (Page and Whitacre 1975, Whitfield 1985, Buchanan et al. 1988, Dekker 1988, Cresswell 1994, 1996), and achieve greatest hunting success using cover to conceal their approach (Whitfield 1985, Cresswell 1994,…”
BackgroundDekker, D. (1998) · The Canadian Field-Naturalist · doi:10.5962/p.358499 · Cited by 32 · see citing works
Self-citationMills, R., Hildenbrandt, H., Taylor, G. K., & Hemelrijk, C. K. (2018) · PLOS Computational Biology · doi:10.1371/journal.pcbi.1006044 · Cited by 30 · see citing works
“Arguably, for the stoop to evolve as an habitual attack strategy, these risks must be outweighed by certain survival advantages, and stooping has therefore been proposed either to save energy [5], or to enhance catch success [6].”
BackgroundFalcon genomics in the context of conservation, speciation, and human culture
Wilcox, J. J. S., Boissinot, S., & Idaghdour, Y. (2019) · Ecology and Evolution · doi:10.1002/ece3.5864 · Cited by 22 · see citing works
“…large and mid-sized falcons, peregrine falcons specialize on other birds, which they usually take with swoops and dives in flight (Cresswell, 1996; Dekker, 1988; Jenkins, 2000; Tucker, Tucker, Akers, & Enderson, 2000), whereas Hierofalco and other member of the clade tend to consume a wider…”
BackgroundHabitat use and foraging behaviour of urban merlins(Falco columbarius)in winter
Warkentin, I. G., & Oliphant, L. W. (1990) · Journal of Zoology · doi:10.1111/j.1469-7998.1990.tb04018.x · Cited by 21 · see citing works
Bourbour, R. P., Aylward, C. M., Tyson, C. W., Martinico, B. L., Goodbla, A. M., Ely, T. E., Fish, A. M., Hull, A. C., & Hull, J. M. (2021) · Ibis · doi:10.1111/ibi.12963 · Cited by 17 · see citing works
Jenny, J. P. (2013) · Cornell University Press eBooks · doi:10.7591/9780801464287 · Cited by 17 · see citing works
Mills, R., Taylor, G. K., & Hemelrijk, C. K. (2019) · Journal of Avian Biology · doi:10.1111/jav.01979 · Cited by 13 · see citing works
“They hunt a wide variety of avian prey using a range of alternative attack strategies (Rudebeck 1951, Dekker 1988, Dekker and Taylor 2005, Zoratto et al.”
BackgroundStevens, L. E., Brown, B. T., & Rowell, K. (2009) · The Southwestern Naturalist · doi:10.1894/mh-19.1 · Cited by 11 · see citing works
“Peregrine falcons prey on a wide variety of birds that are usually, but not always, smaller than themselves (Cade, 1951; Campbell, 1975; Dekker, 1980, 1987, 1988; Pruett-Jones et al., 1981; Verlarde, 1993; Rosenfield et al., 1995; Ellis et al., 2002), and occasionally on large invertebrates,…”
BackgroundBuchanan, J. B. (2012) · Journal of Raptor Research · doi:10.3356/jrr-11-75.1 · Cited by 10 · see citing works
“Merlins (F. columbarius) also prey on shorebirds (Page and Whitacre 1975, Dekker 1988, Buchanan 1996), and use estuarine habitats throughout much of the Peregrine Falcon’s winter range in North America (Warkentin et al. 2005).”
BackgroundProbst, R., Nemeschkal, H. L., McGrady, M., Tucakov, M., & Szép, T. (2011) · Ardea · doi:10.5253/078.099.0102 · Cited by 9 · see citing works
“…prey vulnerability (Cresswell & Quinn 2004), hunting technique (Bijlsma 1980, Hedenström & Rosén 2001, Roth & Lima 2003), predator experience (Dekker & Taylor 2005), cooperative hunting (Bednarz 1988, Ellis et al. 1993), or sample size effects (Page & Whitacre 1975, Dekker 1988) are contributory.”
BackgroundLocal prey vulnerability increases with multiple attacks by a predator
Quinn, J. L., & Cresswell, W. R. (2011) · Oikos · doi:10.1111/j.1600-0706.2011.20088.x · Cited by 8 · see citing works
Glaucous Gull Predation on Dovekies: Three New Hunting Methods
Jakubas, D., & Wojczulanis‐Jakubas, K. (2010) · ARCTIC · doi:10.14430/arctic3335 · Cited by 8 · see citing works
“A similar “stealth hunting” technique, i.e., hunting low over the ground or water surface trying to surprise the prey, has been described in falcons (Bengtson, 1971; Dekker, 1988, 1998, 2003).”
BackgroundDekker, D., & Drever, M. C. (2015) · The Canadian Field-Naturalist · doi:10.22621/cfn.v129i2.1696 · Cited by 7 · see citing works
“After their initial attack fails, first-year falcons commonly persist with long pursuits and multiple swoops at their intended prey (Dekker 1988, 1999).”
BackgroundSelf-citationDekker, D. (2012) · Canadian Journal of Zoology · doi:10.1139/cjz-2012-0213 · Cited by 4 · see citing works
Self-citationDekker, D. (2014) · Natural Areas Journal · doi:10.3375/043.034.0309 · Cited by 2 · see citing works
“From 1965 onward, over 45 consecutive years, I visited the lake on circa 30 days during each spring and fall, less often in summer, to study the interaction of raptors and waterbirds (Dekker 1980, 1984, 1988).”
BackgroundSelf-citationFeeding and predation danger tradeoffs in stopover site usage by western sandpipers (Calidris mauri)
Pomeroy, A. C. (2006) · Summit (Simon Fraser University) · Cited by 2 · see citing works
The allometry of vertebrate pursuit predation
Koopmans, L., de Roos, A., & Martin, B. (2026) · Proceedings of the National Academy of Sciences of the United States of America · doi:10.1073/pnas.2534397123 · Cited by 1 · see citing works
Leonardi, G. (2020) · Springer eBooks · doi:10.1007/978-3-030-60541-4_4 · Cited by 3 · see citing works
Pomeroy, A. C., Seaman, D. A. A., Butler, R. W., Elner, R. W., Williams, T. D., & Ydenberg, R. C. (2008) · Cited by 1 · see citing works
Sprague, A. J., Hamilton, D. J., & Diamond, A. W. (2008)
Marín Sanz, J., Marín-Espinoza, G., & González-Bruzual, L. G. (2021) · Boletín del Instituto Oceanográfico de Venezuela
Effects of management practices on grassland birds: Merlin
Konrad, P. M. (2004) · doi:10.3133/70159827
“During spring and fall, Merlins hunting in pastures and cropland near Beaverhills Lake outside of Edmonton, Alberta, preyed on eight species of sandpipers (Charadriformes) and five species of passerines (Dekker 1988).”
BackgroundInfluentialDiffering Definitions of Falcon Hunting Behavior Metrics Prevent Comparisons of Hunting Success
Buchanan, J. B. (2025) · Journal of Raptor Research · doi:10.3356/jrr2515
Genomic Architecture, Differentiation, and Adaptation in Three Large FalconsPreprint
Wilcox, J. J. S., Arca-Ruibal, B., Boissinot, S., & Idaghdour, Y. (2026) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.64898/2026.05.21.726861
- Authors
- Dekker, D.
- Corresponding author
- Dekker, Dick
- Venue
- Canadian Journal of Zoology
- Publisher
- Canadian Science Publishing
- Published
- 1988-04-01
- Volume
- 66
- Issue
- 4
- Pages
- 925-928
- ISSN
- 0008-4301 (ISSN-L)
- 1480-3283
- OpenAlex
- W2157135563
- Cited by
- 41
- References
- 6
- Citations by year
- 2026: 2 · 2025: 1 · 2021: 2 · 2020: 1 · 2019: 3 · 2018: 1 · 2015: 1 · 2014: 1 · 2013: 1 · 2012: 2
- FWCI
- 1.86
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Canadian Journal of Zoology (publishedVersion)
- Funders
- World Wildlife Fund
- Topics
- Physical Sciences › Environmental Science › Ecology › Avian ecology and behavior
- Physical Sciences › Environmental Science › Ecology › Wildlife Ecology and Conservation
- Physical Sciences › Environmental Science › Ecology › Animal Ecology and Behavior Studies
- Keywords
- Falco peregrinus, Merlin, hunting techniques, predation success, shorebirds, Passeriformes, surprise attack, sex differences in predation, agricultural landscapes, predator-prey interactions
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