In this guide we learn how to tell a Kestrel (Falco tinnunculus) vs Merlin (Falco columbarius)
Quick answer first: Kestrels are the pale, long-tailed hoverers you often see hunting over fields and roadsides; Merlins are chunkier, darker, faster-flying falcons that chase small birds in direct, powerful flight.
General Appearance
![Female Merlin [Left] - Female Kestrel [Right]](https://i0.wp.com/in-focus.info/wp-content/uploads/2025/10/Plate-3-1.png?resize=960%2C540&ssl=1)
- Kestrel: slim, long tail, often hovers or perches on posts; warm rufous back with dark spots (males have a grey head), pale underparts with streaking. Common in open/edge habitats.
- Merlin: stockier and more compact, shorter square tail, fast direct flight with pointed wings; adults show grey (males) or brown (females) upperparts and more uniformly streaked underparts. Often hunts over moorland, coastal marshes or chases small passerines.
Size & shape: what to look for
- Overall size: Both are small falcons, but merlins are noticeably more robust and muscular for their length. They look chunkier in the chest and neck. Kestrels appear slimmer and more delicately built, with a longer, narrower tail.
- Wings & tail in flight: Merlins show shorter tails and sharply pointed, relatively broad wings; their flight is fast and direct. Kestrels have longer tails and a looser flight, often holding wings in a more angular “diagonal” when hovering. Use the wing-tip shape and tail length as quick clues.
Plumage differences (males, females, juveniles)
- Male Kestrel: rufous back with black spots, grey head and tail-base, and a long tail with a dark terminal band; pale, streaked underparts.
- Female/Juvenile Kestrels: are browner and more heavily streaked overall.
- Male Merlin: usually slate-grey above with streaked buff underparts (depending on subspecies/region).
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- Female/Juvenile Merlins: are browner and heavily streaked, but still typically darker and less rufous than kestrels. Merlins lack the pale, strongly patterned “face” and long rusty tones of kestrels.
Behavior: hovering vs. hunting style
- Kestrel: famous for hovering in place (facing into the wind) while searching for small mammals, large insects and reptiles. Also frequently perches on posts, wires, or roadside markers. If you see sustained hovering above open ground, you’re almost certainly looking at a kestrel.
- Merlin: a pursuing predator — fast, direct chases at or through flocks of small birds. You’ll more often see merlins delivering rapid stoops, low-level chases, or high-speed passes rather than hovering.
Habitat & seasonal movements
- Kestrel: broad habitat including farmland, moorland edges, urban parks, even cities. Resident in many areas year-round though local movements occur.
- Merlin: breeds in uplands and tundra in many regions; during migration and winter they move to coasts, marshes, and lowland open country to hunt passerines. You’re more likely to see merlins in places with concentrations of small birds or in coastal marshes in winter.
Short annotated comparison table
| Kestrel | Merlin | |
| Build | Slim, long-tailed | Stockier, compact |
| Tail | Long, narrow, often with dark tip | Shorter, square-tipped with bands |
| Flight | Often hovers; slower wingbeats | Fast, direct, powerful |
| Plumage cues | Rufous back (males blue/grey head) | Males slate/grey; females brown |
| Typical prey | Small mammals, large insects | Small birds, sometimes small mammals |
| Typical habitat | Open farmland, urban edges | Uplands, coasts, marshes (esp. winter) |
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References
- Kane, S.A. and Zamani, M. (2014) ‘Falcons pursue prey using visual motion cues: new perspectives from animal-borne cameras’, Journal of experimental biology, 217(2), pp. 225–234. [Accessed 19/10/2025].
- Leonardi, G. (2025) The History of Western Palearctic Falcons. 1st edn. Cham: Springer. Available at: [Accessed 19/10/2025].
