Breeding

Many aspects of breeding biology remain poorly known. Much of the information that follows is based on limited observations, small sample sizes, or inference from closely related species.

Pair Formation

No evidence of pairing prior to arrival on breeding ground; males begin to arrive before females (see Migration: migratory behavior, above). Pair formation begins as soon as both sexes arrive; display over coastal feeding areas within a few days of arrival in s. Alaska, where appear to pair within a day or 2, then move to nesting areas a few days later. By first week of May in s. Alaska, generally paired and displaying over breeding territories (L. Tibbitts pers. comm., CSE). All breeding activities later at other sites; earliest breeding activity in w. Alaska begins in last third of May (McCaffery and Harwood 2000 McCaffery, B. J. and C. M. Harwood. (2000). Status of Hudsonian Godwits on the Yukon-Kuskokwim Delta, Alaska. Western Birds 31:165-177. Close ).

Nest-Building

Never described, hence little information on timing; presumably occurs during mid-May in Alaska, later elsewhere.

First/Only Brood Per Season

Figure 4. Because of short season at high latitudes, only 1 brood/yr. Average first lay date May 14 ± 6.5 days (n=9) in Susitna Flats, AK. In Churchill, MB, initial lay dates come later, with an average of June 13 ± 7.6 days (n=9). Hatching at Churchill recorded 26 Jun–18 Jul (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close , J. R. Jehl, Jr., pers. comm., Senner et al. unpubl); in Susitna Flats, Alaska between 24 May and 22 Jun. Most broods at Churchill hatch within span of 2 wk (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close ).

Renesting propensity likely depends on climatic conditions during the breeding season. In Churchill, during warm years, 31% of depredated first nests, renested (n=13), while in cold years, 0% did (n=5). In Susitna Flats, 75% of depredated first nests, renested (n=8) (Senner et al. unpubl.).

Selection Process

Multiple scrapes are created within a territory early on during breeding season. Scrapes appear to be reused or improved upon from year to year and renests within one season often occupy a scrape made at the beginning of that breeding season (Senner et al. unpubl.). It is unknown if the female makes the ultimate decision or how this process may play out.

Microhabitat

Most nests placed on dry tops of hummocks, often under dwarf birch, in string-hummock or sedge marsh; occasionally in a tussock of grass or sedge-tundra marsh (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close ). Incubating bird usually well concealed by surrounding vegetation, with some nests concealed from above by overhanging birch, rhododendron, or larch twigs. Tallest shrubs within 1 m of 4 nests in s. Alaska ranged from 16-cm spruce sapling to 2-m Spirea bush; vegetation within 1 m of these nests predominantly sweet gale, moss, and grass, with smaller amounts of rushes, sedges, forbs, lichens, Potentilla, small shrubs, and spruce saplings (L. Tibbitts pers. comm.). At Churchill, nests located on top of hummocks about 110 × 50 cm, and 25 cm high, with tallest sedges and grasses 40 cm high (n = 8; J. R. Jehl, Jr., pers. comm., JK); nests are rarely within one meter of full-grown tree (1-2 m tall), average cover of .9% (n=40). Sedges account for a majority of vegetation covering hummocks (Water Sedge (Carex aquatilus) and Tufted Bulrush (Scirpus caespitosus) the most abundant); rest comprised of birch, dwarf rhododendron (Rhododendron lapponicum), trailing willow (most commonly Salix arctophila), bog rosemary (Andromeda polifolia), blueberry (Vaccinium uliginosum), and sphagnum mosses (Senner et al. unpubl.). No known preferences regarding orientation of hummock, or location of nest on hummock.

Site Characteristics

See Habitat: breeding range, above.

Construction Process

No information. In other godwit species, male makes nest cup by scraping ground with feet and placing vegetation in scrape; females sometimes help (Cramp and Simmons 1983 Cramp, S., and K. E. L. Simmons (1983). The Birds of the Western Palearctic, Volume 3: Waders to Gulls. Oxford University Press, Oxford, UK. Close , Gratto-Trevor 2000 Gratto-Trevor, C. L. 2000. Marbled Godwit (Limosa fedoa). In The Birds of North America, No. 492 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA. Close ).

Structure And Composition Matter

A saucer-shaped depression, pressed into moss or other underlying vegetation. Nest cup may be lined with only a few dead leaves, possibly blown in, or with more substantial lining consisting of, for example: dry leaves of sweet gale and willow, sedge leaves up to 8 cm long, leaves of Potentilla and bog rosemary, twigs 1–5 cm long, spruce needles and twigs, bits of birch, grass, moss, and lichens (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close , L. Tibbitts pers. comm., CSE). Nest often has 2 entrances (JK); see Incubation, below.

Dimensions

Average nest width is 14.3 cm; depth, 4.3 cm. Nests found 0.2-1.0 m above waterline, but this varies throughout the season with rainfall. (n=26 nests in Churchill, MB) (Senner et al. unpubl.)

Microclimate

No information.

Maintenance Or Reuse Of Nests, Alternate Nests

Two instances of nest reuse recorded in Susitna Flats, AK. Two pairs reused nests from the previous season. Neither pair was successful in the second year, but not enough data to draw a conclusion. No known instances of alternate nests. One instance in Churchill, MB, of the appropriation of a Short-billed Dowitcher (Limnodromus griseus) nest (with eggs) by godwit. Nest ultimately held eight eggs—4 godwit and 4 dowitcher—although the dowitcher eggs were eventually pushed to the side and left unincubated. It is not known if these dowitcher eggs were from that year or the previous year (Senner et al. unpubl.).

Nonbreeding Nests

Not known.

Shape

Ovate pyriform.

Size And Mass

In Churchill, average size 53.1 x 35.6 mm (n = 136 eggs over a three year period) 53.1 × 36.1 mm (n = 11 eggs from 3 Alaska clutches; L. Tibbitts, M. Spindler, Senner et al. unpubl.). Extremes for all sites combined: length 48.0–60.6 mm, width 33.1–41.2 mm. Average mass of 8 eggs (2 clutches) from Alaska 31.6 g (range 30–34).

Color

Variable. In Alaska, ground color most commonly Grayish Olive (43; capitalized color names and numbers follow Smithe 1975 Smithe, F. B. (1975). Naturalist's Color Guide. American Museum of Natural History, New York, NY, USA. Close ), but also Olive Gray (42) and Pearl Gray (81); also described as olive buff, light brownish olive, and greenish; darker than yellowlegs' eggs. Sparingly marked with darker spots, including Dark Drab (119B), Grayish Horn (91), Brownish Olive (29), and Olive Brown (28); spots quite small (<3 mm) and finely speckled over egg, irregularly distributed, usually concentrating around larger end (Baicich and Harrison 1997 Baicich, P. J., and C. Harrison (1997). A Guide to the Nests, Eggs, and Nestlings of North American Birds. 2nd edition. Academic Press, San Diego, California, USA. Close , L. Tibbitts pers. comm., CSE).

Surface Texture

Little or no gloss (JK).

Eggshell Thickness

No information.

Clutch Size

Typically 4. Of 52 clutches from Churchill thought to be complete, 4% had 2 eggs, 4% 3 eggs, 92% 4 eggs (mean 3.88; J. R. Jehl, Jr., pers. comm.); of 7 complete clutches in Alaska, 2 had 3 eggs and 5 had 4 eggs (L. Tibbitts pers. comm.). Partially depredated nests are often abandoned, but pairs may continue brooding remaining eggs.

Egg-Laying

No data on timing in relation to nest completion. Eggs generally laid in the late morning. Female will return to the territory and move furtively toward the nest. Laying happens relatively soon after the female is settled on the nest. She then leaves quickly after the egg has been laid. Male is generally present in the territory, more often during the egg-laying period than is the female. Egg-laying, in total, takes 5 d for a 4-egg clutch (Senner et al. unpubl.).

Intraspecific egg-dumping not known. In Churchill, a pair displaced a Short-billed Dowitcher pair from their nest, pushing the eggs to the outside and replacing them with their own.

Onset Of Broodiness And Incubation In Relation To Laying

Continuous incubation begins after the third egg is laid—first by the male and then alternating on a roughly 12-hour rotation (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close ) (Senner et al. unpubl); intermittent incubation may occur earlier, either during day or night (J. R. Jehl, Jr., pers. comm.).

Incubation Patches

Two, symmetrical ovals; well defined in both sexes.

Incubation Period

At 10 nests, 22.5 d (Jehl and Hussell 1966c Jehl, Jr., J. R. and D. J. T. Hussell. (1966c). Incubation periods of some subarctic birds. Canadian Field-Naturalist 80:179-180. Close ) (Senner et al. unpubl.).

Parental Behavior

All details below based on observations of 4 nests at Churchill by JK, unless otherwise noted. Both sexes incubate, females mainly by day (approx. 06:00–18:30 ± 1 h), males by night. Changeover schedule varies greatly among pairs. When not incubating individuals feed, preen, rest, monitor territories from hummocks and treetops, take part in displays with conspecifics, and deter predators (see Behavior: predation, above). Off-duty bird spends most time away from nest-site but probably often within hearing distance, as more often than not it responds to prolonged alarm calls of an incubating male (Gill and Tibbitts 1999 Gill, Jr, R. E. and T. L. Tibbitts. (1999). Seasonal shorebird use of intertidal habitats in Cook Inlet, Alaska. In Final Rep: USDI, U.S. Geol. Surv., Biol. Resour. Div., and OCS Study. Close ).

Incubating bird may sit without moving for several hours; usually does not change direction it faces during an incubation bout. When eggs are well pipped, incubating adults often reposition themselves. Incubating female usually does not react in any visible or audible way to her mate's calls nor to his flying over the nest; only sporadically is female heard to call in duet with conspecific displaying overhead (see Sounds: vocalizations, above). Aggressive behavior toward predators intensifies a few days before hatching (see Hatching, below).

During nest exchanges, off-duty bird flies in calling, and lands about 15–60 m from nest. Incubating bird usually rises and looks around, while partner stands and calls for 1–2 min—a dynamic, hard to localize, whit, whit-wheet, toe-wit, toe wit —before flying to within a few meters of the nest. New arrival approaches slowly, sometimes climbing hummocks and looking around. During approach, may engage in false feeding (even with bill-cleaning motions) and false preening. Incubating individual flies straight out from nest, without calling. New incubator stands 2–5 s, then slowly enters the nest, sits high for a moment looking around, rolls eggs, and settles down.

Nest has 2 entrances, almost opposite (n = 8 nests). Hudsonian Godwits enter only through these entrances and usually face one while incubating. When individual returns to nest after being flushed or to exchange duties, it positions itself facing opposite direction to that faced before (n = 13 returns at 4 nests, JK).

At least in some pairs, changeover occurs at the same time each day until eggs are well-pipped, although at Susitna Flats where non-incubating individuals often feed on nearby intertidal flats, changeover may occur more in line with tidal schedules (Senner et al. unpubl.). Then shift lengths change, and male spends most of the day close to the nest, watching from a high hummock 20–60 m from nest. Off-duty bird rarely observed so close to nest earlier in incubation, except when responding to mate's alarm calls. If a bird that has been flushed from a nest is slow to return, its mate may take over incubation (JK).

Hardiness Of Eggs Against Temperature Stress; Effect Of Egg Neglect

One pair appeared to abandon its nest for two days late incubation because of a disturbance, but returned and eggs hatched on time (Senner et al. unpubl.).

Preliminary Events And Vocalizations

Eggs begin to show cracks 3–4 d before hatching. When first pip holes appear, parents become more aggressive toward intruders. When chicks start hatching, incubating parent becomes even more unlikely to flush from nest, often remaining completely still until the threat is inches away. Non-incubating parent becomes much more hostile to predators during this period.

Shell-Breaking And Emergence

Most common hatching pattern is for first 2-3 eggs to hatch beginning in mid-to-late afternoon and the final egg(s) to hatch the following morning; hatch has not been observed to last for longer than one day (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close , JK, Senner et al. unpubl. data). Chicks leave eggshells through large, asymmetrical openings (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close ).

Parental Assistance And Disposal Of Eggshells

Parental assistance in hatching never observed. Parents will remove eggshells (J. R. Jehl, Jr., pers. comm.). One or 2 eggshells might be left in nest after departure of brood (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close , JK).

Condition At Hatching

Chicks precocial, covered with down at hatching. In Churchill, neonatal mass, 24.9 g; culmen length, 15.7 mm; head length, 38.3 mm; diagonal tarsus 35.2 mm (n = 80). Mean measurements for chicks found in nest cups at Susitna Flats: mass, 25.0 g (n = 106); culmen, 16.8 mm (n = 122); diagonal tarsus, 35.4 mm (n = 122); head length, 38.2 mm (n = 122). One chick with mass of 23.3 g had yolk sac 2.2 g (J. R. Jehl, Jr., pers. comm.). Egg teeth present on tip of upper and lower mandibles; lost as soon as bill dries (Jehl 1968d Jehl, Jr., J. R. (1968d). The egg teeth of some charadriiform birds. Wilson Bulletin 80:328-330. Close , Senner et al. unpubl.).

Chicks able to walk, swim as soon as dry; in favorable weather, they start wandering from parent within an hour or 2 of drying. As soon as chicks leave nest, respond to parents' alarm calls by squatting and freezing; sometimes react to other calls by returning to nest. In one case, brood observed to wander 200 m from nest within 1.5 h after leaving it (JK). See Appearances: molts and plumages.

Growth And Development

See Sounds: vocalizations. Chicks are capable of flight in about 26 d, but often do not undertake flight, even when disturbed, until >30 d (Jehl and Smith 1970 Jehl, J. R., Jr., and B. A. Smith (1970). Birds of the Churchill region, Manitoba. Special Publication no. 1. Manitoba Museum of Man and Nature, Winnipeg, Manitoba, Canada. Close ) (Senner et al. unpubl.).

In Churchill and Susitna Flats, newly hatched birds were tracked and measured weekly until fledging. In the first week, chicks showed an average of 10.9% (± 5.8) increase in mass (n = 32); during the second week, chicks increased mass by 17.1% (± 5.1, n = 13). See Figure 5 for measurements of chicks grown in captivity (Senner et al. in prep).

Mean measurements of four recently fledged birds in late Jul: flattened wing, 201 mm; diagonal tarsus, 61 mm; culmen, 68.8 mm; total head length, 104.8 mm; mass, 234.5 g (L. Tibbitts unpubl.); 2 birds were distinctly smaller in all measures, raising possibility that sexual size dimorphism was already evident at this age.

Both parents provide care. While at the nest, female does not prevent chicks from wandering, or touch or direct them with her bill. She calls chicks to leave the nest; then parents brood chicks, lead them to feeding/hiding areas, alert them to danger, and vigorously deter predators (see Behavior: predation, above). Some brood-rearing areas are used only briefly, others occupied by broods for >2 wk (JK). Usually both parents remain with chicks until they fledge (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close ).

Brooding

Performed by both parents. One female brooded for almost 70% of first 1.5 h after chicks left nest, with brooding bouts lasting 1–14 min; chicks were not brooded during subsequent 1.5 h (JK). Ambient temperature during this period increased from 6.3 to 9.8°C (P. Brown unpubl.).

Feeding

Chicks feed themselves. No data on diet, range of feeding methods, feeding rates, etc.

Nest Sanitation

Not applicable; young leave nest soon after hatch.

Carrying Of Young

Not known; rarely, female will pick up chicks under her wings when she abruptly rises after brooding (JK).

Not reported.

Not reported.

Departure From Nest

Broods leave nest area within a few hours after last chick is dry, stay longer in nests in inclement weather; typically depart within 6–18 h (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close , JK). Before departure, chicks spend time under parent and wander around nest area on their own. Most broods leave nest together; in some, male leads older 2 chicks away when they are several hours old. In such cases, female remains at nest, but male will join her if she utters alarm calls; within 24 h, she leads remaining chicks from the nest (JK).

At departure, parent walks away from nest, calling constantly with soft, quiet wheet, wheet and toe-wit, toe-wit; chicks follow 2–3 m behind, peeping. During departure, attending females observed to glean insects from low vegetation without slowing down—one jab on each step; also seen to oil feathers and to stretch leg, wing, and neck. Chicks maintain vocal contact with and follow parent; approach to be brooded following parental calls and squat in response to alarm calls.

Growth

No information beyond first 17 d. See also Young birds, above.

Association With Parents Or Other Young

At Churchill, during dry years, multiple broods may congregate loosely around remaining tundra ponds. At Susitna Flats, broods rarely within 100 m of each other (Senner et al. unpubl.). Male and 3 recently fledged young reported in mixed-species brood aggregation with Bristle-thighed Curlews and Whimbrels (McCaffery and Harwood 2000 McCaffery, B. J. and C. M. Harwood. (2000). Status of Hudsonian Godwits on the Yukon-Kuskokwim Delta, Alaska. Western Birds 31:165-177. Close ).

Ability To Get Around, Feed, And Care For Self

Chicks precocial. Female often abandons the brood first (around 20 d), with male often staying until chicks are completely Volant (around 30 d).

No information.