Breeding

Pair Formation

Spring migrants occur in flocks of 2–20 birds at sites just south of breeding grounds (T. Randall in Bannerman 1961). Pairs begin to form within a few days of arrival on breeding grounds, most formed by mid-May.

Nest Building

Scrapes found from late Apr to mid-May in Alberta (T. Randall in Bannerman 1961).

First/Only Brood Per Season

Typically, birds begin to lay eggs 12–15 d after arrival on breeding grounds (T. Randall in Bannerman 1961, TLT). In Québec, the only confirmed nest of Lesser Yellowlegs was found on 13 Jun (Gauthier and Aubry 1996). In Ontario, a 2-egg nest was found on 4 Jun and downy young on 9 and 10 Jul (Peck and James 1983). In Manitoba, egg dates range from 10 Jun to 10 Jul; hatch generally occurs the first week of Jul (Jehl and Smith 1970). In Alberta and Manitoba, 38 clutches were found 15 May–16 Jun (Bent 1927); a nest with 2 eggs found on 1 May in Alberta was considered unusually early (T. Randall in Bannerman 1961). First hatchlings in Alberta detected on 4 Jun (Street 1923). In British Columbia, 5 clutches were found 4–16 Jun; of 21 broods found between 13 Jun and 17 Jul, over half (12/21) found 24 Jun–3 Jul (Campbell et al. 1990). In the Northwest Territories, eggs collected 15–20 Jun near Fort Anderson (R. MacFarlane in Cooke 1910) and 1 Jun at Fort Resolution (Kennicott in Cooke 1910); 1 nest hatched between 29 Jun and 5 Jul and newly hatched young noted on 21 Jul on the Mackenzie River delta (Porslid 1949). In s. Yukon Territory, 15 records of flightless young ranged in date from 17 Jun to 23 Jul (P. Sinclair pers. comm.). In ne. Alaska, 3-egg nest with incubating bird discovered on 20 Jun; almost volant chicks and fully-feathered young seen on 27 Jul and 2 Aug, respectively (Kessel and Schaller 1960). In n.-central Alaska, nest with 4 slightly incubated eggs found on 13 Jun (Irving 1960). In sw. Alaska, newly hatched chicks found between 14 and 27 Jun at Lake Clark National Park (P. Tomkovich unpubl.), and median hatch date was 12 Jun (range = 1 Jun–5 Jul, n = 3 yr) in upper Cook Inlet (TLT unpubl.). See also Figure 4 .

Second Brood Per Season

Nests and downy young found as late as early Jul at many sites suggests renesting occurs after eggs are lost, but never documented with marked individuals. Most likely, only single brood raised per season.

Selection Process

No information.

Microhabitat

Typically nests on dry, mossy ridges or hummocks, next to fallen branches and logs, and underneath low (<1 m) shrubs or small (1–2 m) trees (Rowan 1929, Campbell et al. 1990, WFVZ Nest Record data). Sites densely vegetated and often characterized by standing dead shrubs or trees. Numerous species of plants reported in vicinity of nests, especially birches (Betula spp.), willows (Salix spp.), sweet gale (Myrica gale), Labrador Tea (Ledum groenlandicum), arctic rose (Rosa acicularis), aspen (Populus tremuloides), poplar (P. balsamifera), and black spruce (R. MacFarlane in Bent 1927, WFVZ Nest Record data). Nests usually well hidden and difficult to detect, although a few records of relatively exposed nests that were visible from a few meters (e.g., Irving 1960). Nests typically between 30 and 200 m of a water source, such as a marshy lake outlet, drainage ditch, salt-marsh pool, river, lake, or slough (Street 1923, WFVZ Nest Record data), but also found within meters of small pools (Campbell et al. 1990, Kessel and Schaller 1960) and up to 850 m from any wetland (WFVZ Nest Record data). Nests in coastal Alaska were on average 332 m ± 302 SD (range = 10–840, n = 17) from the wetland that was subsequently used as first brood-rearing destination; in most cases, this was the one closest to nest (TLT unpubl.). See also Habitat: breeding range, above, and photographs in Street (1923) and Rowan (1929).

Site Characteristics

See Habitat: breeding range, above.

Construction Process

Little information. One male created scrape by crouching and pressing breast into moss; mate perched nearby. Incubating birds add material to nest (L. Oring in litt.).

Structure And Composition Matter

Depression in ground or moss, lined with dry grass, decayed leaves, spruce needles, moss and twig fragments, and other debris (Street 1923, T. Randall in Bannerman 1961). Lining consists of leaves and fragments of plants in immediate vicinity of nest (WFVZ Nest Record data, Irving 1960).

Dimensions

In Alberta, nest cups measured 89–102 mm in diameter and 32–38 mm in depth (Street 1923). Seventeen nest cups in Alaska had an average outside diameter of 105 mm ± 23 SD (range = 70–135); mean depth with lining was 25 mm ± 8 SD (range = 12–40); mean depth without lining was 42 mm ± 9 SD (range = 30–60; TLT unpubl.).

Microclimate

No data. Typical nest sheltered on 1–3 sides by logs, sticks, or vegetation. Some completely surrounded by tall grass and sedge.

Maintenance Or Reuse Of Nests, Alternate Nests

Two instances of nest-cup reuse in a 4-yr period; 1 pair reused their nest cup after skipping a year during which they had paired with other mates, and another pair reused a nest cup that had been used by a different male (and possibly a different female) the previous year (TLT).

Nonbreeding Nests

Multiple scrapes constructed within 1–75 m of the one ultimately selected; birds may line many scrapes before laying eggs in one (Bent 1927, Rowan 1929).

Shape

Ovate pyriform (Bent 1927).

Size And Mass

In Alberta, eggs from 25 clutches (n = 98 eggs) averaged 42.34 mm in length (range = 38.99–46.40) and 29.21 mm in breadth (range = 27.56–30.95; WFVZ). Eggs from 13 clutches in Alaska (n = 51 eggs) averaged 42.32 mm in length (range = 40.84–44.55) and 29.33 mm in breadth (range 28.12–30.53; TLT unpubl.). Mean mass of 43 eggs from Alaska (n = 11 clutches) was 17.4 g (range = 14.5–20.4); the eggs that weighed the least were the ones measured closest to hatch. One 4-egg clutch 13 d prior to hatch weighed 91% (71.0 g) of the associated female’s body mass at hatch (TLT).

Color

Ground color of eggs from 4 clutches in Alaska was smoke gray (44 and 45) and markings were a wide variety of browns, including sepia (119), burnt sienna (132), raw umber (223), mars brown (223A), burnt umber (22), dusky brown (19), fuscous (21), natal brown (219A) (color names and numbers after Smithe [1975–1981]). Other authors describe eggs as follows: ground color of medium buff to buffy brown with vandyke-brown or purplish-gray spots (T. Randall in Bannerman 1961); ground color of pale olive green or greenish buff to coffee brown, with markings of reddish brown and dark chocolate overlaying pale purple (Street 1923); ground color of olive buff to cream buff or, less commonly, honey yellow to cartridge buff or light pinkish cinnamon to pinkish buff, with small markings of chocolate, liver brown, bay, and chestnut brown overlaying larger blotches of purple drab and ecru drab (Bent 1927). One albino egg was creamy white with a few small pale-brown spots (Bent 1927). Markings concentrated at larger end of egg and patterns similar within a clutch.

Surface Texture

Slightly glossy (Bent 1927).

Eggshell Thickness

Mean empty shell weight 0.873 g (range = 0.709–1.027) in 25 clutches (98 eggs) collected before 1947 when DDT was first widely used (WFVZ).

Clutch Size

Usually 4. Single records of 5- and 6-egg clutches, and several reports of nests with 3 well-incubated eggs; the 6-egg clutch incubated by 2 adults simultaneously (T. Randall in Bannerman 1961). Nineteen of 20 nests in s.-central Alaska contained 4 eggs, the remaining nest held 3 eggs and probably was a replacement clutch, because it was initiated late in the season (TLT).

Egg-Laying

May not commence for several days after nest cup constructed (T. Randall in Bannerman 1961). Females lay eggs consecutively at daily intervals (R. Harlow in WFVZ Nest Record data, TLT).

Onset Of Broodiness And Incubation In Relation To Laying

Incubation appears to begin with the laying of the second egg, i.e., birds flushed from 2-egg nests return promptly to resume incubating (T. Randall in Bannerman 1961, TLT).

Incubation Patches

Bilateral and in both sexes.

Incubation Period

Twenty two to 23 d (T. Randall in Bannerman 1961).

Parental Behavior

Incubation shared by both parents (WFVZ Nest Record data, L. Oring in litt.). Incubating birds wait for mates to approach before leaving nest. Pairs may perform brief relief ceremonies or incubating birds may leave before relieving birds arrive at nest, but as soon as they land nearby (L. Oring in litt.). Birds travel the last several meters to nest on foot (Rowan 1929).

Hardiness Of Eggs

Of 15 complete clutches that survived to hatch: 12 hatched 4 chicks, 2 hatched 3 chicks and contained single unhatched eggs with under-developed embryos, and 1 held 4 eggs with fully-developed embryos that failed to emerge after pipping their eggs (TLT).

Little information. Eggs in a few nests hatched within 2–12 h of each other (Street 1923, TLT). Starred about 3 d and pipped about 1 d before hatching (TLT).

Parental Assistance And Disposal Of Eggshells

One bird flew from nest with eggshell in bill and dropped it about 50 m away (D. Ward pers. comm.). Only small bits of eggshells found in recently hatched nests.

Condition At Hatching

See Appearance, below. Precocial, although movements slow and not completely coordinated until several hours post-hatch. Most chicks lose egg tooth before leaving nest (TLT). Eighteen incubator-hatched chicks from Manitoba weighed on average 11.97 g (SD = 0.96) within 6 h of hatch (Ricklefs 1984). For 103 chicks captured within 1–24 h of hatch in Alaska, average mass (g ± SD) was 11.1 ± 1.2, average length (mm ± SD) of exposed culmen and diagonal tarsus were 12.7 ± 0.9 and 31.1 ± 1.3, respectively (TLT unpubl.). Hatchling’s culmens are about 35%, and tarsii about 60%, of adult length.

Growth And Development

No available information.

Brooding

Both parents brood. Chicks brooded in nest for up to several hours after hatching, thereafter outside the nest for short bouts (sometimes only seconds) at frequent intervals over the next few days at least. Chicks solicit brooding by peeping loudly as they walk toward parent. Adults give soft kip, cup, and keup notes to direct chicks toward themselves. Brooded in typical manner; i.e., parents face chicks, crouch, and ruffle breast feathers so that chicks can burrow easily into them (Fig. 5). Parents will brood young chicks under stressful circumstances (e.g., when humans within meters).

Feeding

Chicks feed themselves upon departure from nest. Peck at insects and insect larvae on ground, in water, off plant stems, and out of air. Initially, both parents lead brood to foraging areas (Street 1923, T. Randall in Bannerman 1961).

Nest Sanitation

Not applicable.

Parental Carrying Of Young

Never observed.

Not known to occur in this species.

Not known to occur in this species.

Departure From Nest

Young depart nest within several hours of all eggs hatching and once all chicks are dry (Street 1923, L. Oring unpubl.). Initially, broodmates stay close together and are found within centimeters of each other. In one case, however, a male led 3 chicks to nearby pond a few hours after last egg hatched while female remained overnight in nest cup with chick that hatched last; both parents and brood were together 20 h later (TLT). Within days chicks begin to wander; 5-d-old broodmates often found about 25 m apart. To move brood, a parent flies ahead of chicks, lands on tree or ground, and gives cup and kip calls to encourage chicks to move toward it. Meanwhile, the remaining parent scans for predators from vantage point near brood and walks along with any slow-moving chicks. As brood proceeds, chicks pause frequently for foraging or brooding.

Association With Parents, Or Other Young

Most broods cared for by both parents for first several days after hatching, thereafter by single parent, generally male. In Alaska, females on average attended brood for 11 d (range = 4–16 d, n = 18 broods) and males for 26 d (23–31 d, n = 10; TLT unpubl.). Length of brood attendance appeared related to habitat conditions and time of season. In years with relatively abundant wetland habitat, males remained with broods 2–4 d after chicks fledged, whereas when wetlands limited, males deserted broods immediately after chicks fledged. Females of late-hatching broods attended them for fewer days than females of early-hatching broods.

Ability To Get Around, Feed And Care For Self

Chicks precocial (See Parental care: feeding, above). Time between hatching and first flight 22–23 d, and time between hatching and independence 23–31 d (TLT unpubl.).

After fledging, immatures make local movements to nearby staging areas where they join flocks of conspecifics and other shorebirds (T. Randall in Bannerman 1961). At coastal breeding areas in Alaska, immatures may remain on adjacent upland brood-rearing areas for 2–3 d after last parent has departed before joining shorebird flocks on coast (TLT).