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

Breeding

Introduction

Cavity breeder, normally monogamous, sometimes raises two broods in a season.

Phenology

Sequence and relative timing of breeding events is similar across the range, though specific dates depend on the region of study. Dates of spring arrival at breeding areas across the range serve as a general guide to timing of the breeding season in those areas (see Migration: Timing and Routes of Migration), though post-arrival conditions can have a greater effect on timing of clutch initiation than arrival date itself (106; see Conservation and Management, Effects of Human Activity).

Pair Formation

Males usually arrive first; courtship begins as soon as females arrive (206). Pairs form quickly. In Sweden, where most arrival was in the second half of April, most pairs had formed by 25 April (207). Ages of male and female in pairs are highly correlated (87).

Nest Building

Sites are chosen and nest building begins shortly after pair formation, such that in Sweden, early arriving females start building about 3 weeks after arrival (207). Intervals are shortened for late-arriving females (208, 106). For speed of construction see Nest.

First Brood

Time elapsed between pair formation and clutch initiation varies widely with year both among and within sites (207). In northern regions, nest-building is rapid and laying typically begins about 3 weeks after settlement (114, 209, 207, 210); about the same time that cloacal protuberance develops (2–3 weeks after arrival, then lasting at least 13 days after date of first egg; 187). On average, females in Sweden start to lay 2.8 d ± 2.7 SD after nest completion (range 0–11, n = 29) (207). Peak initiation of first clutches on Skokholm Island, Wales, was 1–10 May (4); median date in Germany was 4 May (211). In south-central Sweden, median date advanced from 17 May during 1993–2004 to 13 May during 2005–2017 (D. Arlt, personal communication). Timing of first eggs is much later in montane and arctic regions: mid-June in the Swiss Alps (C. M. Meier, personal communication), and the last 10 days of June in the Yamal Peninsula and in Koryak Highlands (1). Correspondingly, peak fledging in lowland Europe is about 2 weeks earlier than in Transbaikalia and about a month earlier than in montane and coastal tundra (1).

Clutch initiation of leucorhoa in Iceland occurs in mid to late May (confirmed records in eBird), and in last week of May in Greenland (114, 209), although very early nests may be initiated there in mid-May (4). At Iqaluit, Baffin Island, clutch initiation of probable first broods over a 6 yr period was 29 May–27 June (median 11 June, n = 71; DJTH).

Second/Later Broods

Birds must arrive relatively early and also initiate first broods relatively early if there is to be time for a second brood (101); however, most females having time to raise a second brood do not attempt to do so (101, 28).

The estimated interval between fledge of first brood and laying of first egg in second clutches on Baffin Island is 4–7 d (28). On Skokholm Island that interval is 5.7 d ± 3.5 SD (n = 28) (4), though occasionally a female initiates a second clutch laying before first-brood young have left the nest (206, 4). The intervals between first and second broods are similar to those between loss of clutch and start of a replacement clutch: 5 d in Sweden (n = 11; 207), and 5.9 d ± 1.6 in Germany (211).

Molt often overlaps with care of young in second broods, especially for males (27, DJTH, Figure 2). At high altitudes molt can overlap with first broods (1; see Appearance: Molts).

Nest Site

Selection Process

Females choose nest sites alone; males may stimulate females’ activity by singing (4). Site-selection behavior only gradually changes to nest-building behavior (2). A female may select several sites and carry nesting material into several holes before making a final choice (206, 4, JK).

Microhabitat

Minimizing chances of predation is likely a factor in choice of specific sites for nesting, though evidence is lacking on which features are relevant. In the United Kingdom, preferred burrows are at least partly covered in 60–100 cm tall grass (4), and have entrances about 10–15 cm in diameter (206). Nests are usually placed about 30 cm into the burrow regardless of cavity length, or farther when holes are wide (206), leaving at least 10 cm of space between the nest and the farthest end of the cavity (206, 4, 1). Nests of leucorhoa in Greenland can be a meter or more deep within rock crevices and cavities (29). Disturbance causes nestlings and adults to retreat deeper into cavities and side niches, and adults often exit from another opening (184, DJTH); however, it is not known whether sites offering extra protections are selected.

In northern and montane regions, south-facing slopes are the first to be occupied (84; C. M. Meier, personal communication), and the distribution of snow when males arrive affects selection of a nest site (96; DJTH). Most nests in Iqaluit, Baffin Island were 4–130 m above high-tide mark (n = 159; DJTH), and in Greenland nests were rarely found above 600 m (29), but at more southerly latitudes breeding can occur at much higher elevations: 1,800–2,400 m in the Swiss Alps (C. M. Meier, personal communication) and above 2,500 m in Iran (80).

Selection of location for a nest is influenced by microclimate. On Skokholm Island, Wales, most entrances faced away from prevailing winds (4). Where climate is harsh, burrows are frequently selected even when rock cavities are plentiful, presumably for their more stable microclimate (1). At high altitudes in the Tien Shan, for example, 19 of 30 nests were in burrows of marmot (Marmota spp.).

Site Characteristics

Nests are built in holes, though open nests are occasionally reported (212, 213, 4). Most holes are in the ground or close to ground level, but at one site 20% of nests were under roof tiles on farm buildings, at least 8–10 m above ground (214), and in two cases Swedish birds nested in tree holes 3–5 m high (D. Arlt, personal communication). Range-wide the typical nest site is among or under rocks or in rock crevices; or in burrows excavated by other animals, especially where alternate cavities are not available (206). A wide variety of man-made cavities are used: under boards or in pipes on the ground, in cavities on building exteriors, crannies in piles of construction rubble or metal dumps, in piles of firewood (in Russian taiga; 1), abandoned farm machinery (D. Arlt, personal communication) and even in abandoned boots and artillery shells (4). Typical nest boxes are rarely used (1), but artificial sites designed for Northern Wheatear are often accepted (215, 216; see Conservation and Management: Management).

Of 185 nest sites in Iqaluit, Baffin Island, 59% were under or amid large boulders and 37% in deep vertical or horizontal cracks in rock faces. Only 12% were at least partially accessible by humans (DJTH), and most sites had more than one exit route . About 10% of sites were created by human activity, mainly rubble piles , but single nests were also found in partially buried pipe, under scrap plywood, in the eaves of an abandoned building, similar to a site described by 61), in the foundations of a driveway and of a house. Some nest cavities were up to 150 m from a suitable foraging area (DJTH). Use of tundra remnants as small as 0.5 ha suggests that area sensitivity is not affected by presence of buildings when broader expanses of suitable foraging habitat are close by (DJTH).

Animal burrows are common nest sites in Europe, mainly those of rabbits (Oryctolagus; 161) but also a few of Manx Shearwater (Puffinus puffinus) and Atlantic Puffin (Fratercula arctica; 4) and in one case the burrow of a vole (D. Arlt, personal communication). In Russia, burrows of souslik (Citellus spp.) and pika (Ochotona spp.) are used, and north of the Arctic Circle, burrows of lemming (Lemmus spp.), arctic fox (Vulpes lagopus), and Bank Swallow (Riparia riparia; 1).

Nest

Construction Process

Nests are built solely by females, although occasionally a male will pick up nest material and carry it to a prospective hole (4, 211, JK; D. Arlt, personal communication). Materials are picked up or wrenched from plants and may be struck on the ground similar to manner of subduing large prey (4). The male usually perches close to the nest site and watches, sometimes uttering zweng notes or singing (4, B. McCaffery in 56); he may also accompany the female while she collects material, wing-flicking and bobbing (4).

Nests in Sweden were completed in 3.2 d ± 1.4 SD (range 2–7, n = 13); more quickly by females with longer tarsi (207). Duration of building appears broadly variable: 4 d minimum (1), 1 wk (212), and up to 2 wk on Skokholm Island, Wales, where females visited nests 0–35 times/h in the 7–10 days before laying of the first egg, 0–9 times/h in the 3–7 days before laying and 1–2 times/h in the last 2 days (4). Nest construction is more rapid for replacement and second-clutch nests (4).

Structure and Composition

Nests of oenanthe generally consist of a foundation, cradle, and cup (4). On Skokholm Island, the foundation is a large untidy mass of dried stems of bracken (Pteridium aquilinum), wood sage (Teucrium scorodonia), ling (Calluna vulgaris), and other plants, occasionally accompanied by larger feathers of gulls. The cradle holds the cup and is made of smaller materials, while the cup is more tightly bound together and is easily separated from the cradle because of its texture. Cups on Skokholm Island had no distinct lining of wool or feathers but commonly consisted of fibrous materials such as bentgrass (Agrostis spp.), mosses, lichens, avian contour feathers, mammal hairs, and leaves. All nests observed on the Shetland Islands, Scotland, had a mass of cow hair in the cradle and a great many small feathers in the cup (184).

Few nests of leucorhoa have been described. The bryophyte Calliergon sarmentosum figured prominently in two nests in Greenland, along with heads and roots of grasses (217). Elsewhere, a single nest had a bulky, loose foundation of dry stems of grass, sedge and forbs; and a cup lined with feathers of ptarmigan (Lagopus muta), dog wool and few human hairs (61). The few visible nests on Baffin Island were also lined with feathers (DJTH).

Dimensions

Nest dimensions depend on size of the nesting chamber (79). On Skokholm Island, nests were as much as 25 cm across, with walls ~2.5 cm thick; cup ~7 cm across and ~5 cm deep. Bulky nests (including foundation) can weigh > 100 g (4). The cup of a single leucorhoa nest in eastern Canada was 6.5 cm across and 4.0 cm deep (61).

Microclimate

No data comparing ambient temperatures with conditions at the nest, although site selection is clearly influenced by microclimate (Nest Site).

Maintenance or Reuse of Nests

Nests may be reused for replacement clutches, but generally are not for second broods (76, 206, 4, DJTH). Three second nests on Baffin Island were 120, 350, and 720 m distant from sites of the successful first nests (28).

Some nest cavities are occupied in multiple years, even in localities that seem to have no shortage of suitable locations. For nest burrows studied over 6 years on Skokholm Island, 5% were used more than once (n = 185), about half the cases involving the same pair (4). Five percent of 185 nest sites on Baffin Island were also reused, 6 sites for 2 years and 4 sites for 3 years—though never by the same individuals (DJTH). One distinctive site photographed in 1953 (76) was also used by a Northern Wheatear pair in 2007 (DJTH). Whether the nest itself is reused is usually unknown, but one cavity in Greenland contained 8 nests on top of one another (218).

Nonbreeding Nests

None known.

Eggs

Shape

Subelliptical (2).

Size

Table 1. Eggs in first clutches are slightly but not significantly longer than eggs in second clutches (4). Length and width are positively correlated (n = 180; 180). Over 70% of variation both in egg size and in mass are attributable to between clutch variation (207).

Mass

Table 1. Mean mass of oenanthe eggs on Skokholm Island, Wales, declined through the season: 2.98 g ± 0.99 (n = 17) for eggs laid in the first week of May, 2.77 g ± 0.24 for second week of May (n = 17), and 2.80 g ± 0.36 (n = 28) for the third week of May (4). Larger females tend to have larger eggs, and the last egg tends to be heavier, especially in large clutches (180). Egg mass on Skokholm averaged 12% of female body mass (4).

Eggshell Thickness

Information needed.

Color and Surface Texture

Varies from very pale blue or even white (184) to blue green. Smooth with low to moderate gloss, unmarked or with a few red brown flecks primarily at the broad end (2, DJTH). Causes and correlates of color variation have not been studied.

Clutch Size

Mean clutch size of subspecies oenanthe increases roughly with latitude, ranging from 3.5 to 7 eggs (Table 2). Few nests of leucorhoa were found by DJTH prior to hatching, but mean brood size for Iqaluit, Baffin Island was 7.2 (n = 22; 28).

Size of first clutch declines through the season (4, 207, 210, 211): in England, decreasing from 6.1 to 3.9 eggs (n = 228; 4); in Germany, from about 5.1 to 3.9 eggs (211); in Sweden from about 6.8 to 5.9 eggs over the month of May (214). Replacement clutches are laid if nest loss occurs early; these are smaller than the clutches being replaced (35, 207), sometimes significantly so (e.g., 6.25 vs. 5.29 eggs at a site in Sweden (D. Arlt, personal communication). Genuine second clutches are usually smaller than the first (206), but in Transbaikalia the mean first clutch was 5.31 eggs (n = 29) while second clutches averaged 5.75 eggs (n = 24), possibly related to conditions improving as the season advanced (1).

Females have a significant tendency to produce the same clutch size in different years (210).

Egg Laying

Eggs are generally laid 24 h apart (206); in England before 7:30 GMT, but delays and even skipping of days may occur in cold weather (4).

Incubation

Onset of Broodiness and Incubation in Relation to Laying

Incubation begins with last or next-to-last egg (2, DJTH).

Incubation Patches

The female has a single abdominal patch (JK).

Incubation Period

Incubation usually lasts 13–15 d (206), but ranges from 10–18 d; poor weather leads to lengthier incubation period (4, 207). Means for 3 consecutive years in Sweden were 12.3 d ± 0.79 SD (n = 11), 14.0 d ± 1.46 SD (n = 17), 14.3 d ± 0.90 SD (n = 11; 207). On Skokholm Island, Wales, mean incubation period decreased with date in the season: mean in May was 13.1 d (range 10–16) vs. mean in June of 12.8 d (range 11–15). Incubation period also decreased with clutch size (4); but whether date and clutch size have independent effects is unknown.

No data on length of incubation period from the Nearctic or from hotter and more arid parts of the breeding range.

Parental Behavior

Only the female incubates (2, JK). The male commonly remains near the nest while his mate incubates, at least during the first 4–5 d, and with varying levels of attentiveness. He may sing softly at the cavity entrance and occasionally may enter briefly, sometimes resulting in the female departing. A female may also leave the nest if her mate gives anxious weet calls (4). Though males rarely feed incubating females, it has been observed (2; T. Pärt, personal communication).

Mean percentage of daylight spent incubating on Skokholm Island was 71% (range 57–77, n = 12 nests); the mean length of individual bouts was 16.3 min ± 10.2 (n = 463 bouts at 7 nests); but was 26–45 min at an eighth nest. Breaks between bouts averaged 7.5 min ± 3.1 SD (n = 423 at 15 nests; 4). Mean bout length at a single leucorhoa nest on Baffin Island was somewhat longer: 30.9 min ± 12.2 (n = 82), averaging ~28 min for 2 days and ~40 min over the next 2 days (DJTH); however, total time spent incubating daily remained consistent at 63–66% of the total active period—similar to the total time for oenanthe on Skokholm. Females spend more time in the nest during warmer conditions (both daily and across seasons), as well as when provided experimentally with extra food, indicating that length of incubation bouts is constrained by the need for the female to replenish her energy (219).

Females ending an incubation bout behave differently than those feeding young; they often pause, stretch and/or preen at the cavity entrance, then fly to a foraging area with undulating flight typical of the Northern Wheatear, looking for possible intruders or predators. Thereafter they commonly sit and clean the beak before flying directly back to the nest (4), a behavior that incidentally helps researchers locate nest sites (DJTH). During breaks from incubation, females using the pause and travel technique (see Diet and Foraging: Feeding) searched more rapidly, paused less and captured more prey items than did males and non-incubating females, suggesting lowered prey selectivity (206).

Hardiness of Eggs Against Temperature Stress; Effect of Egg Neglect

Incubation period is longer when conditions are poor (207). Partial hatch failure is frequent at some sites (see Demography and Populations: Measures of Breeding Activity); causes not studied in most cases.

Hatching

Preliminary Events and Vocalizations

Information needed.

Shell-Breaking and Emergence

Egg tooth assists the hatching process (4). Hatching on Skokholm Island (n = 78 clutches) was completed in 1 d (35% of clutches), 2 d (47%), and 3 d (18%) (4). Hatching is more synchronous in smaller clutches (220).

Parental Assistance and Disposal of Eggshells

Parents are not known to assist. Eggshells are removed from nests and deposited at varying distances (4); up to 50 m (221). Small pieces of shell may be left behind in the nest lining (222).

Young Birds

Condition at Hatching

Naked; pinkish skin shows 5 feather tracts; down is dark gray (223, 4, JK, DJTH). The bill has a lemon yellow cere and the gape is yellow (4); inside of mouth is pale orange with no spots (2, DJTH). Average mass of oenanthe at hatching on Skokholm Island was 2.8 g (n = 167; 4).

Growth and Development

An excellent and lengthy account of behavior of nestlings (4) is summarized here: at 1 d gape and defecate; at 3 d give Food-Begging calls and yawn, ears and eyes open; at 5 d react to shadows; at 6 d stretch wings; at 7 d stretch legs, preen; at 8 d face entrance of burrow, stand, climb on rim, grasp with claws, explore by pecking, shuffle wings; at 9 d localize sound; at 10 d give Contact Call; at 12 d temporarily venture outside cavity entrance, hop and scramble, cower; at 13 d give rudimentary tchi call; at 14 d display full soliciting posture, flutter wings, bob in anxiety.

Growth rate and asymptotic mass vary among study sites and subspecies (DJTH, Figure 6); also among years within study sites (180), and among young in the same nest (4).

Tarsi grow up to age 9 d and are sufficiently large for ringing chicks at day 4 (224).

Feather sheaths on various tracts show as small black spots beneath the skin, first piercing the skin at day 4 from tracts around the eye, on the nape, and on tibiotarsus (4). Primary sheaths break the skin about day 5 (DJTH, Figure 7) and primaries break from sheaths at about 7–9 d (223).

Within nests, broods of nestlings can maintain stable body temperature of 38°C for about 12 min in the absence of brooding by 5–6 days of age. Without the insulation of siblings, nest, and nest cavity, individual nestlings do not reach that standard until 10 or 11 days (n = 10; 223).

Skull ossification of juvenile leucorhoa is more than half, but less than fully complete at the end of August (n = 4; DJTH). The egg tooth, prominent at hatch, disappears gradually over the nestling period (4). The bill of juveniles is at first smoother and less decurved at the tip than in older birds, but takes the adult form during the first fall (123).

Sex Ratios and Sex Allocation

Secondary sex ratio among nestlings (excluding unhatched eggs and pre-sampling losses) has been studied in Sweden (D. Arlt, personal communication). Among 294 nestlings in 54 broods (30 in 2001, 24 in 2002), overall proportion of males was 0.43; significantly different from parity. Difference in male proportion between years (0.43 vs. 0.36) was not significant.

Parental Care

Brooding

Only the female broods young. When eggs begin to hatch she spends as much time covering young as she did incubating eggs; a mean of 50–60% of the day in the chicks’ first day (4, 173). That proportion declines to 5–10% by day 6; about the age at which broods within the nest can resist rapid cooling (223). How long brooding continues varies considerably among nests, but is not significantly affected by ambient temperature (173). Length of brooding bouts in Sweden did not change significantly with chick age, averaging about 10–15 min (173).

Feeding

Daily feeding activity on Skokholm Island began about 0.5 h prior to sunrise and ended about 0.5 h after sunset, for an average working day of 17.1 h; this was little affected by lengthening daylight as the season progressed (n = 85; 4). Feeding days were longer in Sweden, where daylight is longer, averaging 19.5 hours and also encompassing dawn and dusk (225); average time of first visit was 0315 (range 0214–0506) and of last visit was 2250 (range 2109–2340). Length of working day was very similar in Iqaluit, Baffin Island, where July nights darken to civil twilight (sun slightly below horizon, but light sufficient for ordinary outdoor activity): 19.9 h ± 0.46 SD for females and 19.2 h ± 0.97 SD for males (n = 18; DJTH). Average time of first feeding visit in Iqaluit was earlier for females than for males: 0501 (n = 26 nights) vs. 0536 (n = 28; all times Eastern Daylight Savings Time, about 34 min earlier than solar time). Activity ceased at the same time for both sexes, on average 2354 for females (n = 19) and 2358 for males (n = 20; DJTH). Working day at a Greenland site where the sun does not set during the breeding season was similar to that in Iqaluit: 19.25 h for both sexes (n = 4 nights at 1 nest; 226); however, the average times for start and end of feeding visits in Greenland were ~2 h later than in Iqaluit: 0711 to 0226 for the female and 0740 to 0253 for the male (local time ~42 min earlier than solar time).

Minimum nocturnal rest period, even in continuous daylight, is about 4.5–5 h. A single female in Greenland rested an average 4.75 h (range 3.82–6.30) and her mate for 4.78 h (range 4.28–5.25; 226). Rest periods for females in Iqaluit were similar to those in Greenland: 4.6 h ± 0.6 SD (range 4.1–5.6; DJTH). Male rest periods were longer: 5.4 h ± 1.7 SD (range 3.1–9.4), but omitting anomolously high rest periods (> 8 h) for one male that may have been tending some young already out of the nest, the average was close to that for females: 4.7 h ± 0.8 SD (range 3.1–5.9; n = 15 nights from 6 nests; DJTH).

Timing of nocturnal rest period in Iqaluit corresponded quite closely to times of lowest temperature (Figure 8; DJTH), when insects and spiders are least active. A relationship between rest periods and temperature was less clear in Greenland (226); the authors suggested that parental rest periods are likely adjusted to local prey availability rather than to temperature per se.

Number of parental feeding visits/h increases with age of young (4). Total feeding visits in Sweden were about 10/h through day 4, rising to 15/h by day 7 and reaching a plateau of about 25/h by day 9 (173). Results from Skokholm Island were similar: visits increased to 15/h on day 5 and remained at about that level until day 11, when they rose again to > 20/h (4). Hourly feeding rate of leucorhoa on Baffin Island also began at about 10/h on day 1, but rose fairly steadily thereafter to the much higher level of 45/h on day 12 (n = 393 h at 4 nests; Figure 9, DJTH).

Feeds/nestling/h in the Netherlands averaged 5.1 ± 0.8 SD (n = 3,354 feeding events at 19 nests), with little variation among brood sizes except that singletons were fed 8–12 times hourly (161). In Sweden, feeding rate per nestling was about 2/h up to day 7, then rose to about 6/h by day 11 (173).

Overall visit rates for oenanthe on Skokholm Island were 5.2/h by males and 12.4/h for females (n = 131 h at 6 nests; 4). Male leucorhoa in Iqaluit, Baffin Island fed proportionally more than males on Skokholm Island: 12.5 visits/h vs. 14.8/h by females (n = 393 h at 4 nests; Figure 10, DJTH). A Swedish study showed males made proportionately more feeding visits than females (58%) when females were still spending time brooding small nestlings (0–3 days old; n = 100 nest visits sampled at each of 12 nests), but females made proportionately more feeding visits (54%) in later stages, when chicks were 7–9 days old (n = 13 nests; D. Arlt, personal communication).

Both size of prey and number of items delivered in a single load increase with nestling age (173). Males in Sweden delivered more items per visit (1.7 items ± 0.4 SD, n = 45) than did females (1.5 items ± 0.4 SD, n = 49), especially at the beginning and end of nestling period, but sexes did not differ in composition of prey delivered (173). Load sizes of 1.7 items per visit were also delivered in the Netherlands (161). Continuous camera records of nest visits on Baffin Island were inadequate for determining average load size, but did show that while many loads were small, they commonly consisted of several items and sometimes at least 5–6. Parents feeding active older nestlings regularly tilt their heads 90° to that of the young (DJTH), possibly facilitating complete food transfer.

Feeding rate of Northern Wheatear is correlated with temperature (225), which itself correlates positively with insect activity. Hourly feeding visits increase rapidly in first the 2–4 hours after adults start their day, but patterns thereafter are variable. Sometimes there are morning and evening peaks with a mid-day lull (e.g., 4); sometimes peak occurs at mid-day (225).

To meet the energy needs of young, each parent has to bring 3 times as much food per day as needed for itself (180). Males and females do not differ in the proportions of each foraging technique used during the nestling period (170). Adults forage closer to the nest when feeding nestlings (175).

Nest Sanitation

Both parents eat fecal sacs during first 3 days after hatch; thereafter fecal sacs are usually carried 30–100 m from nest, occasionally < 30 m (76, 4, JK). Once nestlings start venturing out of the cavity, fecal sacs accumulate outside the entrance (4)—good signs of a successful nest (DJTH). Females are usually more active than males in removing feces (4). In Iqaluit, average rate of fecal sac removal (0600–2200) was 2.7/h ± 1.1 SD for females and 1.3/h ± 0.5 SD for males (n = 393 h of observation at 4 nests). However, while males at 2 of 4 nests barely participated at all, males at the 2 other nests removed almost as many fecal sacs as did their mates (DJTH).

Carrying of Eggs or Young

Damaged eggs may be removed from the nest and carried up to 50 m away (227). Occasionally intact eggs are found outside the nest cup, often close to the nest but sometimes in the passage to entrance (D. Arlt, personal communication).

Cooperative Breeding

Failed breeders and floater males are known to set up prospecting territories for future use, typically where there are currently active nests (194). Such males are often seen carrying food (T. Pärt, personal communication), and may account for records of extra males delivering food to nests. That behavior has rarely been recorded for oenanthe (215), but for leucorhoa on Baffin Island it appears quite common; recorded at 1 of 4 nests watched closely by Sutton and Parmelee (76), and at 2 of 4 nests continuously monitored by camera (DJTH; Figure 10). At one of the filmed nests, the extra male made 1–11 visits on each of the 9 days of filming, all during the hours from 1300 to 0100. He was caught on camera near the nest entrance after young began leaving the nest, but it is unknown whether he fed fledglings. The extra male at a second nest (Figure 10, where filming started only after young were well developed), provided food regularly; visiting 7.1 times/h in the 3 days prior to fledging and 2.7 times/h in 2 days after young started to leave the nest. In neither case did the extra male remove fecal sacs. When extra males met with one of the resident pair at the cavity entrance they were largely ignored (DJTH).

Brood Parasitism by Other Species

Historic records document occasional brood parasitism in the Old World by Common Cuckoo (Cuculus canorus), but there are no recent observations (228). Range of Northern Wheatear in the Nearctic does not overlap that of the Brown-headed Cowbird (Molothrus ater).

Fledgling Stage

Departure from the Nest

The nestling period ends with nest departure rather than fledging per se, as most departures occur before the young can fly. The usual age of final departure is given as 15–16 days of age (206, 163); on Skokholm the average was 15.4 d ± 2.3 SD (range 10–21) (4). In the few days prior to leaving the nest for good, active nestlings move to the cavity entrance and sometimes beyond. Parents often pass them by and carry food inside; possibly the reason that chicks at the entrance usually hurry back inside when an adult approaches (DJTH; behavior mentioned also by Conder [229]; ). Heavier nestlings are the first to venture from the nest (163).

True abandonment of nests on Skokholm Island appeared to happen suddenly over the course of one day, evidently without adult prompting (4). Fledglings hopped quickly away from the nest entrance and dove into holes more than a few meters away, never to return. Nest departure was more prolonged on Baffin Island, where some young remained in the nest a day or two after others had departed (DJTH), possibly related to asynchronous hatch in the larger broods of northern regions. Once some young had left the nest, feeding visits to the nest declined, especially by males (Figure 10). Over the first 1–3 days after some fledglings had left the nest for good, nest visits dropped from 16.0/h pre-fledge to 7.2/h for females, and from 13.1 pre-fledge to 3.5/h for males (n = 8 days at 4 nests). Most males ceased visiting completely before the second or third day after first departure (Figure 10). The last few visits made by adults, sporadic and widely spaced, were without food (DJTH); possibly adults were checking to ensure no young were left behind.

Within 24 h of nest departure, fledged broods disperse between 10–70 m from the nest cavity and may remain there for a few days (163, 4). On Baffin Island fledglings within the first day or two of departure were usually found about 100 m from the nest site (range 30–200, n = 7); variation appeared related to the distance required to reach a suitable foraging area (DJTH).

Growth

See Young Birds. Birds leave the nest at full size in terms of mass, but feather growth is incomplete and new fledglings flutter-hop to move around. Length of primary 7 at nest-leaving is about half of final length (Figure 7; mean for immatures captured in August = 79.6 ± 2.6 mm, n = 33; DJTH). The stubby tail is only full grown by about 23–24 days (4). Preformative Molt begins at about 5–6 weeks (see Appearance: Molts).

Association With Parents or Other Young

About a week after nest departure, broods on Baffin Island had moved a mean of 370 m from the nest site (range 200–1,000 m, n = 12; DJTH); a previous report from the same site reported a 2.4 km movement (76). Only two broods were observed in the second week after nest departure, one within 300 m of the nest and the other 3.5 km distant (DJTH).

During the first week out of the nest the young do not wander. They stand on prominent perches waiting to be fed, and frequently seek shelter in cavities. By the second week they become highly mobile and follow their parents, spending increasing amounts of time in aggressive attacks or chases of siblings (163).

Brood division between parents is common and is established between 3 and 6 days after nest departure (163). Young quickly recognize which parent will feed them and cease chasing the wrong parent. Adults continue to feed young for at least two weeks after they leave the nest, during which there is a gradual decrease in parental responsiveness to chasing and begging by the young; feeding rate declines from about 0.4 feeds/min to < 0.1/min by 11–12 days after nest departure (163).

Adult oenanthe starting second broods tolerate the presence of independent young from their first broods, as long as the latter remain about 5 m from the nest (4). In leucorhoa, by contrast, juveniles have been reported associating with adults feeding nestlings and even helping to feed the young (29, 218); such juveniles are most likely offspring of the adults’ first brood.

Ability To Get Around, Feed, and Care for Self

Juveniles can make short flights within a week of leaving the nest (76) and in the second week they spend about 25% of their time in flight (163). Daytime use of cavities chosen as shelters during the first days after nest departure declines as flying skills develop, ceasing at about 10 days out of the nest; overnight roosting in the cavities continues until the young are fully independent (4).

Self-feeding begins about 6–8 days after nest leaving (230). By 3 days post-departure, young start displaying ground-gleaning behavior (See Diet and Foraging: Feeding). Perch-to-ground sallying and aerial hawking are observed by day 5 or 6. The proportion of successful prey attacks increases gradually from zero to 10–20% by 3 weeks out of the nest (163).

Immature Stage

Young appear fully independent of parents by 28 days of age, or about 2 wk after nest departure (4). They begin to chase other species, and to display the same behavioral patterns used by adults when responding to conspecific warnings or to threat (4; see Sounds and Vocal Behaviors and Behavior: Agonistic Behavior). Males perform Zigzag Flight when 3–4 wk old and may sing short subsongs by 1 month of age (4)—elements of behavior that establish a mobile individual area that later develops into a mobile individual territory. Immatures often form groups of 5–20 individuals from several different broods and remain in them (with some interchange) for several weeks; through preformative molt and up to the start of migration (T. Pärt, personal communication). See Demography and Populations, Population Spatial Metrics.

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