SPECIES

Northern Wheatear Oenanthe oenanthe Scientific name definitions

Erica H. Dunn, David J. T. Hussell, Josef Kren, and Amelia C. Zoerb
Version: 2.1 — Published October 25, 2022

Demography and Populations

Measures of Breeding Activity

Age at First Breeding

First breed at one year old (2). All females mate, but 5–26% of males with territories may remain unpaired, mainly later-arriving first-year males (210).

Intervals Between Breeding

Annual breeder.

Clutch Size and Number of Clutches per Season

Mean clutch size of subspecies oenanthe increases roughly with latitude, ranging from 3.5 to 7 eggs (Table 2). Replacement clutches are laid if nest loss occurs early. See Breeding: Eggs.

Number of Broods Normally Reared per Season

Second broods are fairly common in southern portions of the European breeding range, though annual and site variation is high. Rates of double brooding in England range from rare (93) to ~15–50% (206, 4, 101). Rates elsewhere include 25% in France (89) and 0–54% in the Netherlands (161). In Germany, 10–33% of pairs had second broods, 22% of older pairs vs. 8% of first-time breeders (n = 368 pairs over 3 years; 211). Second broods are rare in northern Europe: only 0–3 cases per year detected in a Swedish population of 80–125 pairs (87).

Rates of second brooding show similar geographic variation in eastern portions of the range, occurring in about 70% of pairs in Transbaikalia, very few at high elevation sites in the Tien Shan mountains, and none in the Chuya Steppe region of southern Altay (1).

Second broods by leucorhoa in Iqaluit, Baffin Island were attempted by about 6% of females (estimated range 4–15%; 28). Observations of juveniles interacting with adults near late nests suggest some double-brooding in Greenland (see Breeding: Fledgling Stage), and double-brooding also occurs “sometimes” in Iceland (231).

For timing of broods, see Breeding: Phenology.

Annual and Lifetime Reproductive Success

No published information on lifetime reproductive success.

Hatching success varies widely. One (rarely two) eggs failed to hatch in up to half of nests at one site in Sweden, where overall hatch failure was 5–8% (n = 46 nests; 33); at another site it averaged 6% (range 4–9%, n = 54 nests; 161), and at two German sites the rates were 3 and 5% (211). Elsewhere, hatch failure can be much higher: 20% at a site in England (n = 17 broods; 187); and 24% in Transbaikalia (15% in nests with at least some hatch; 1). Causes rarely known, though hatch failure of 27% at a site in the Netherlands was associated with high levels of dioxin-like compounds in eggs (232).

Of the eggs that hatched on Skokholm Island, 84% in first clutches resulted in fledged young (n = 402), as did 86% of eggs in second clutches (n = 124; 4).

Overall proportion of nests that fledged young in the Netherlands was 0.43 (range 0.34–0.52; 161); for three sites in Germany: 0.53, 0.75 (211), and 0.73 (77); in France: 0.68 for first broods (n =76) and 0.82 for second broods (n = 34; 89); on Skokholm Island: 0.7 ( 4). On Baffin Island, 81% of leucorhoa nests found primarily during the nestling stage produced at least some young (n = 32 nests from a single year; DJTH).

Mean numbers of young fledged/pair at five sites in England were 2.3, 2.7, 4.2, 4.7 and 5.1 (206); at two sites in Germany: 3.6 and 4.2 (211); and at one site in Sweden: 5.6 ± 1.1 SD (n = 54; 207). At another Swedish site, young fledged/pair declined over 20 years from 4.7 to 3.1 as habitat quality declined (233).

Rates of breeding success depend on several factors, often interrelated.

  • Greater success is achieved by early breeders (101, 77, 214, 234), and early breeders are primarily older birds. Experienced males arrived in Sweden 6–9 days ahead of young males (26) and most (86%) were mated to older females (n = 385) (224).
  • Reproductive success and population growth rates in Sweden are highest in short-grass habitat (224, 235, 236, 26), in part because adults using those habitats have greater foraging efficiency and lower rates of nest predation, leading to higher survival rates (237). Better access to high quality habitat is the main factor in greater breeding success of males older than two years (224, 235).
  • Predation in Sweden on nests of yearling males (33.5% of 391 nests) was higher than for nests of older males (25.7%, n = 586), in large part because older males made up 62% of breeders in short grass areas, where predation rates (about 20%) were half as great as in taller vegetation (224). About 40% of nest predation occurred during incubation and 60% in the nestling period (n = 923 nests; 238), and nest predation was highest early in the breeding season (214).
  • Level of predation strongly influences nest success. Protection of nests from red fox (Vulpes vulpes) increased fecundity (239). Fledge success for nests in high quality habitat was 90% in roof nests (largely safe from predators) vs. ̴ 60% for ground nests (214). In Sweden, 20% of nest losses were caused by death of female during predation events (237).
  • Females in better condition (body mass/tarsus length) have larger broods (207).
  • All components of breeding success decline with delay in date of first egg (214, 234). Multifactor modeling indicated seasonal decline for first broods in clutch size (~7 to 5.5), number of fledglings (~5.3 to 3.5) and recruits to future breeding population (~0.9 to 0.4); see Figure 2 in Low et al. (240).
  • Harsh weather results in longer incubation, greater delay in replacement of failed nests, increased starvation, prolonged nestling growth and lower condition at fledge (180). Rates of nest visitation and survival of chicks decline as amount and duration of rain increases (239). Although most starvation of young occurs late in the nestling period, birds of any age that are lighter than their siblings are the most likely to die, putting asynchronously hatched young at a disadvantage (220).
  • Research methods can affect breeding success in some cases. Handling of females on the nest during laying (and sometimes during incubation) can cause desertion (4). Individual oenanthe carrying geolocators arrived in Sweden later than control birds, began nesting later, and had lower nest success (241).

Life Span and Survivorship

Less than half of breeding adults breed more than once, and fewer than 20% breed more than twice (Table 3). Less than 2% survive beyond 5 years (93, 214). The longevity record as of 2017 was held by a 10 year-old Swedish bird recaptured at its nest (242).

Several European studies have calculated survival rates using multistate mark-recapture models. A Swedish study with known dispersal rates within 6 km of the study site (see Movements and Migration: Dispersal and Site Fidelity) found annual survival of adult males varied among breeding habitats, ranging from 0.34 to 0.62 (n = 564 records of 329 males; adjusted for dispersal and probability of resighting; 87). Survival was higher for males than females (0.50 ± 0.02 SE vs. 0.42 ± 0.02 SE), largely due to higher predation of females nesting in less-preferred taller grass habitat (237). Similarly, survival at three sites in the Netherlands with low dispersal among them was higher for males (range 0.54–0.63) than for females (range 0.40–0.51) (88). Other mark-recapture estimates of adult survival include 0.41 ± 0.08 SE in Spain (n = 289; no effect of elevation either on survival or proportion of transients; 243); 0.46 ± 0.05 SE at an isolated French site (n = 157; 89), and 0.48 in a small Scottish population (90). Food supplementation to breeding adults can increase survival by 20% (90). Parental survival is reduced when workload of foraging increases, as when there is sustained rainfall during the nestling period (239), or when breeding in tall grass territories (237).

First-year survival in a long-term Swedish study varied among habitats from 0.17–0.32 (87), and ranged among three sites in the Netherlands from 0.29–0.32 (88). Other estimates include 0.21 ± 0.05 SE in France (89) and 0.18 in Scotland (90). Early fledging broods have higher apparent juvenile survival than late-fledging broods: 0.31 ± 0.09 SE vs. 0.17 ± 0.06 SE (244). Food supplementation to nestlings can increase their survival by 50% (90). Sustained periods of rain during the nestling period can reduce future recruitment by 50% (239).

Disease and Body Parasites

Disease

Information needed.

Body Parasites

Of 51 spring migrants examined at first landfall in the United Kingdom, 4% carried the tick Hyalomma marginatum (mean of 4 ticks per infested bird); this tick is a vector of Crimean-Congo haemorrhagic fever virus, which can cause severe human disease (245). H. rufipes was found on a spring migrant through Italy (246).

Proctophyllodidae feather mites include Proctophyllodes hipposideros (247) and, uncommonly, P. ciae and P. schwerinensis (248). Feather mites were found in 78.9% of 147 breeding oenanthe in Spain (249). The median number in one wing of infected birds was 5, vs. a mean of 21.8 ± 36.7 SD, and was unaffected by temperature or elevation. Wheatear nestlings often have feather mites (76, 4), occasionally enough to cause mortality (88). Rhinonyssid mites were found in 3 of 91 wheatears from northern Russia (250, 251); one identified to species is Ptilonyssus motacillaes (252).

Gamasid mites of 11 species were found in 9 of 15 nests in Russia (253). The most commonly found (in 8 of 9 nests) was Paragamasus, a species also found in southwestern Greenland (unpublished data cited in Makarova et al. [253]).

Other recorded parasites include: a nematode (Microhadjelia multipapillata); fleas (Siphonaptera: Ceratophyllus borealis, C. gallinae, C. garei, Dasypsyllus gallinulae); lice (Mallophaga: Menacanthus exilis, Ricinus sp., Docophorulus sp.); blood-sucking flies and fly larvae (Hippoboscidae: Ornithomyia avicularia, O. chloropus) (252); blowflies (Calliphoridae: Trypocalliphora braueri, Protocalliphora azurea) (D. Arlt, personal communication); a Haemoproteus blood parasite (254), and a coccidian (Isospora) (255).

Causes of Mortality

Exposure

Cavity-nesting protects most nestlings from exposure. Adults may die in unusual weather events, as when “a great number” died in northeastern Greenland when caught in a late-winter storm on 5 May 1937 (256).

Depredation

See Behavior: Predation. Predation is a common cause of nest failure in Northern Wheatear (details in Measures of Breeding Activity), particularly at sites where most nests are in rabbit burrows (88). Mustelids and snakes are responsible for 65% of nest predation in Sweden; mammalian predators there include short-tailed weasel (Mustela erminea), least weasel (M. nivalis), red fox (Vulpes vulpes), European badger (Meles meles), and domestic cat (Felis catus (257). Elsewhere, some nests are lost to garden dormice (Eliomys quercius; 211), and a few are dug up by dogs (Canis lupus) or taken by Norway rat (Rattus norvegicus; 4). On Baffin Island, leucorhoa adults reacted strongly to short-tailed weasel, which can probably access most cavities; destroyed nests in rubble or dirt (< 10% of all sites) were excavated by red fox, local children, and likely also by arctic fox (Vulpes lagopus).

Avian predators can rarely access nests, but Common Raven (Corvus corax) and various crow and gull species will eat nestlings when they can (4, DJTH). Broods are occasionally dug out from burrows by Great Black-backed Gull (Larus marinus) and Herring Gull (Larus argentatus) (4). Raptors are the main predators of birds capable of flight. Northern Wheatear made up 7% of 930 items taken by Merlin (Falco columbarius) in Scotland, about 75% of them juveniles (258). In western Greenland, Northern Wheatear comprised 4% of 411 identified prey items at two nests of Peregrine Falcon (Falco peregrinus) (259).

Domestic cats are known to take migrants at stopover sites (260).

Direct Human Impacts

In the 1700s, large numbers of wheatears were captured in England in the August–September open season; accounts indicate two people could run 500–700 traps, capturing up to 1,000 birds a day, and more than 20,000 were snared annually on the Sussex Downs. Sold for food, they were considered “delicate and tasty” according to Pennant (1766) (cited in Conder [4]). Large numbers were still being caught in England at the end of the 1800s (222), and the species is still hunted elsewhere. Recoveries of individuals ringed in Britain and subsequently taken by hunters (n = 100) indicated a shift in core hunting pressure from Portugal, Spain, and southwestern France during the 1950s and 1960s towards Morocco, which accounted for 42% of hunting-related recoveries between 1970 and the 1990s (50). Migrating individuals are captured at desert oases in Libya with homemade traps baited with mole crickets (Gryllotalpa spp.) (1).

The larger human impact today is indirect (see Conservation and Management: Effects of Human Activity).

Population Spatial Metrics

Individual Distance

Individuals in groups maintain distance of about 3–5 m, although separation decreases if there is potential danger (4).

Territory Size

Size of territory is inversely related to population density (208, 2, 4), which in turn is influenced by the distribution and patchiness of favored vs. unfavorable habitat (4, 101). For details on territorial behavior, see Agonistic Behavior: Territorial Behavior.

Territory size reported from intensive studies in favored grassland are typically in the range of 0.5–5 ha: mean 1.5 ha (range 0.48–3.30, n = 99) on Skokholm Island (4); 2.25 ha (range 0.90–4.65, n = 94) in Öland, Sweden (33). Smaller territories have been reported in Russia: 0.16 to 0.4 ha in the Moscow region (2) and 0.8 to 1.9 ha in central Asia (1); but territories in colder regions can be much larger: average 8.7 ha (range 5.3–13.5) for an alpine population (261), and 12–16 ha for leucorhoa in Greenland (29). However, these larger numbers may reflect low breeding density without regard to the size of area actually defended.

Another index of defended territory is the mean distance between nests. Mean distances on Skokholm Island were 65 to 85 m (range 16–146) when more than 30 pairs bred, but expanded to 266 m (range 90–570) when only 14 pairs bred (2). In central Asia, distances averaged roughly 70 m (range 50–30; 1), but elsewhere in Russia means were 240 m ± 17 (minimum 112 m, n = 16; 262). In the most densely-occupied area of Iqaluit, Baffin Island during the two years of most intensive nest searching, average distance between nests was 347.5 m ± 172.1 m (range 94–945, n = 74; DJTH). Minimum distances from all studies are typically about 50 m; a notable exception being one record of two nests 15 cm apart that were tended simultaneously by two pairs (184).

Territories are established in the non-breeding season (see Behavior: Agonistic Behavior). Areas defended temporarily during migration range from about 0.1–0.7 ha (4, 124), similar to size of territories on overwintering grounds in northern Nigeria that are about 0.4 ha both for adult and first-winter oenanthe (94). However, overwintering territories elsewhere are much larger: about 2.0–4.0 ha in Senegal and Zambia, and 2.5 ha in Kenya (195, 44).

Home Range Size

In dense populations, home range is effectively the same as territory size; studies of low-density populations have not distinguished between territory and home range.

Population Status

Numbers

Number of oenanthe breeding pairs was assessed in the late 1990s as 2.5–3.7 million in Europe (about 2 million of them in Scandinavian countries), 1–10 million in European Russia, and 50–500,000 in Turkey, for a total of 3.5–14.2 million pairs in those regions (50). That figure has since been revised to 5.3–15.8 million pairs (8), but still omits much of the north Asian breeding range. Population size in North America (oenanthe and leucorhoa combined) is estimated at 260,000 individuals (95% CI: 200,000, 380,000), with 190,000 in Alaska and 78,000 in Canada (263). The total global population is likely between 10 and 500 million mature individuals (8).

Breeding density in the United Kingdom is typically 3–20 breeding pairs (bp)/km2 in the south and 5–20 in the north (50); much lower (0.72 ± 0.11) on moors in Scotland whether managed for grouse or not (264). Density in Slovakia is similar to that in the United Kingdom, at 6–7 bp/km2 (157). Sites selected for long-term study typically have high local breeding density: up to 23 bp/km2 on Skokholm Island and 35/km2 in Breckland, United Kingdom (206, 50); an estimated 26/km2 in Uppsala, Sweden (196), and about 30/ km2 in the Swiss Alps (C. M. Meier, personal communication).

In Transbaikalia, where 80% of all oenanthe pairs are associated with human settlements, mean density is 15–16 pairs/km2 (1). A similar pattern is found also in leucorhoa. Breeding density in arctic regions can be very low; an estimated 0.8/km2 in eastern Baffin Island (218) and 0.2 bp/km2 in western Greenland (57), whereas relatively high densities in other parts of Greenland may be associated with human settlements: 6.1 bp/km2 at Nuuk/Godthåb (217), 7 bps/km2 in a coastal area in Qeqertarsuaq/Godhavn, and 7.8 bp /km2 in Ilulissat/Jakobshavn (57). The example of Iqaluit, Baffin Island exemplifies this pattern. In 1953, Sutton and Parmelee (76) found 5 nests within the roughly 45 km2 area that is now Iqaluit, for a density of about 0.1 bp/km2; at the time there was only a small hamlet of about 1,200 people. The same area was studied by DJTH 50 years later, after Iqaluit had become a territorial capital of 7,500 with greatly increased footprint of government, airport, and residential buildings. Nest density in the largely natural areas surrounding the town was still quite low, 0.3 and 0.6 bp/km2 in the two years of most intensive nest search, but much higher within the town: 4.0 and 4.1 bps/km2 (DJTH; see Breeding: Nest Site).

Trends

Population trends in North America are unknown. In contrast to European regions, human development in arctic regions frequently leads to a local increase in Northern Wheatear numbers (1, DJTH).

Although globally the species is secure, Northern Wheatear has disappeared from many places in western Europe, where it was once widespread in rural areas; see Conservation and Management: Effects of Human Activity for causes. The Pan-European trend for oenanthe from 1980–2009 indicates an annual rate of change of -3.65%, representing an overall decrease of 66% (265). Numbers in the Netherlands declined by 87% between 1990 and 2010 (266), and in Sweden by 61% between 1976 and 2001 (267); Northern Wheatear is threatened with extinction in Germany (268). For supplementary information on country-specific numbers and distribution of declines in Europe, see IUCN.

No information available on trends in subspecies other than oenanthe, but there may be sufficient long-term migration studies on leucorhoa for a multi-site analysis to investigate whether the decline in spring migrants reported by Desaever and Bairlein (104) has been noted elsewhere.

Population Regulation

Populations in Sweden are regulated primarily by quality of breeding habitat. Population growth rate is positive for birds breeding in pasture with short grass, but negative in crop lands and ungrazed grassland with taller vegetation. The differences are due largely to increased survival of first-year and adult birds breeding in good habitat—the result of lower predation and higher foraging efficiency (87, 269; see Measures of Breeding Activity). In some populations, protection of nests from predation, or food supplementation to breeders, can change population growth rate from negative to positive (see Conservation and Management: Management).

The most important component of population stability in the Netherlands was rate of immigration (88). Although rate of immigration was low: 0.17 to 1.25% of the number of females present the previous year, that influx was essential to sustain the small, isolated study populations. A similar population in coastal France was also projected to further decline in the absence of immigration (89).

Recommended Citation

Dunn, E. H., D. J. T. Hussell, J. Kren, and A. C. Zoerb (2022). Northern Wheatear (Oenanthe oenanthe), version 2.1. In Birds of the World (P. G. Rodewald and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.norwhe.02.1