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

Conservation and Management

Not globally threatened (Least Concern) (8). Despite severe decline in some regions (see Demography and Populations: Population Status), the global population is large, estimated at 10–500 million individuals, and the species is very broadly distributed. Legally protected in most European countries and in Russia, as well as Canada and the United States.

Effects of Human Activity

Habitat Loss and Degradation

Populations have declined in many European countries because of habitat loss to agriculture and urbanization. A variety of changes have combined to produce large effects overall; for example, gradual decrease in sheep farming has greatly reduced the extent of the short turf preferred by the species (270, 271), and viral disease has reduced populations of European rabbit (Oryctolagus cuniculus) that keep duneland grasses short and provide a source of nest burrows (88, 272). In Sweden, declines of mixed farming in agricultural regions and of small farm operations within forested areas has reduced the extent of favored habitat (267). Northern Wheatear is mostly gone from Switzerland’s Jura region in large part because of stone crushing that smooths rocky areas for agricultural purposes, but also due to fertilizing, earlier and more frequent mowing, and encroachment of woodland (273).

Habitat can be degraded as well as lost entirely. A 20-year decline in demographic rates at a long-term study site in Sweden may have resulted from deterioration in habitat quality (233).

Fragmentation of habitat restricts movement among populations. Small, isolated populations in the Netherlands and Germany were found to differ little in levels of heterozygosity (indicating that isolation occurred recently), but strong differentiation in 22 microsatellite markers demonstrated reduced gene flow, such that genetic drift and inbreeding are looming threats (274).

Effects of Invasive Species

Information needed.

Hunting and Trapping

See Demography and Populations: Causes of Mortality.

Pesticides and Other Contaminants/Toxics

High hatch failure (27%) in relict populations in the Netherlands is associated with high accumulations of dioxin-like compounds in eggs, to which Northern Wheatear is moderately sensitive, but additional factors may also be contributing (232). Analyses of feathers showed no concerning levels of cadmium, lead, or mercury (202).

Collisions with Stationary/Moving Structures or Objects

Collisions with cars, windows, and lighthouses accounted for about 20% of the 174 recoveries of individuals ringed in Britain for which cause of death could be determined (50). Only low numbers are killed colliding with offshore platforms in the North Sea (275). Nests in industrial and construction sites are sometimes inadvertently destroyed (77).

Other Human Impacts

Climate warming may eventually constrict range in southern areas where breeding is mainly confined to high-altitude montane areas; however, it should also allow nesting at higher altitudes through much of the range where permanent snow currently persists into the summer. Climate warming does affect timing of breeding. Rising March temperature was correlated with earlier arrival of first-spring individuals in Ireland (276). In Belgium, spring migration was earlier in years with higher May temperatures, and mean passage advanced between 1990 and 2018 by 2.9 d in females and 2.5 d in males (104). Whether changes in timing have demographic consequences, however, is not clear. At a site in Sweden where dates of mean arrival and egg-laying advanced about 5–6 days over 24 years, early arriving females did not initiate egg-laying sooner, but rather increased the interval between arrival and clutch initiation; late-arriving females were the most likely to be impacted by any advancement of resource availability resulting from climate change (106).

Breeding success is generally unaffected by onsite research activity. Although parents may desert nests when directly disturbed during egg laying, and sometimes during incubation of completed clutches (4, JK), the normal research practice is to capture and handle adults only when they are feeding young, at which point desertion does not occur. Rates of nest predation are also unaffected by visiting nests to band nestlings or by human scent (T. Pärt, unpublished data in 257).

Study of movements with geolocators do incur a cost to birds. Compared to controls, individuals carrying geolocators in Sweden tended to have lower apparent survival, later arrival and egg-laying, and lower nesting success (25% vs 78%) than control birds (241).

Management

Conservation Measures and Habitat Management

Habitat quality and immigration rates are key factors in population growth (see Demography and Populations: Population Regulation). Conservation at landscape scales should aim to preserve a patchwork of suitable breeding sites within distances that enable gene exchange. It will be important to preserve existing small populations, which in turn may require conservation measures tailored to each site, such as protecting nests where predation rates are high, or increasing the area and quality of preferred habitat (88). In Berlin, Germany, urban sites of 5–7 ha used by breeding individuals could be maintained with mowing and provision of nesting structures (77). Food supplementation to breeding pairs can increase local apparent survival (90), so might be an option for sites where nestling starvation is common. Artificial nest sites can be provided in favored short-grass habitats where natural nest-sites are lacking.

Loss and degradation of non-breeding habitat merits greater attention. Migrants use a broad range of habitat types, but tend to concentrate in sites with abundant food (see Habitat: Habitat in the Nonbreeding Range). Conservation of high-quality stopover sites is especially important for those regions close to oceanic and desert barriers where stopovers are prolonged both in spring and fall as birds prepare for or recover from long flights (63, 68; see Movements and Migration: Timing and Routes of Migration). Overwintering habitat is perhaps of lower conservation concern, in part, because Northern Wheatear often make use of degraded natural habitats (277), but also because low-quality areas can be avoided as birds move among overwintering areas separated by hundreds of kilometers (63, 68).

Effectiveness of Measures

Improvement of habitat to preserve and increase breeding populations can often be accomplished with mowing or grazing, and has the potential to reverse local population declines. Models based on data from a 24-year breeding study in Sweden indicated that changing the proportion of high-quality, short-grass habitat occupied by older males each year would have changed the actual geometric mean growth rate of 0.99 (range 0.97–1.01) to a positive 1.08 (range 1.05–1.11) (269). In the first year after wire-mesh structures were installed in the Netherlands to prevent predators from excavating burrows, predation by red foxes dropped to zero and fecundity of females rose to 5.27, double the average of 2.60 over the previous 4 years (88).

Food supplementation of breeding pairs on Fair Isle, United Kingdom, led to 1.22 times higher annual survival of the adults over controls, and 1.56 higher survival of juveniles (whether or not their parents were fed); enough to reverse the rate of population growth from negative to positive (90).

Artificial nest structures can attract individuals to habitats that lack natural cavities. Old ammunition cans measuring 36 × 18 × 9 cm that were half-buried in a stretch of shore in England were readily accepted, increasing the local population from 26 to 70 pairs in 2 years (215). In Turkmenistan, metal pipes of internal diameter of 4.7 cm and a length of 80 cm were also successfully used (216).

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