Table 6.4. Clutch sizes of birds observed nesting in forest and pastures in Monteverde.
Species Clutch Size Species Clutch SizeForest interior species
Black-breasted Wood-Quail (1)
Sunbittern (2)
Ruddy Pigeon (3)
Chiriqui Quail-Dove (4)
Buff-fronted Quail-Dove (5)
Squirrel Cuckoo (3)
Green Hermit (3)
Purple-throated Mountain-gem (3)
Orange-bellied Trogon (3, 6)
Resplendent Quetzal (7)
Emerald Toucanet (8)
Spotted Barbtail (9)
Northern Barred-Woodcreeper (4)
Eye-ringed Flatbill (3)
Pasture and Edge
Common Pauraque (14)
Stripe-tailed Hummingbird (3)
Hoffman's Woodpecker (3)
Brown Jayb (15, 16)
House Wren (12, 17)5 2 1 1 2 2 2 22-3
2
3-5
2 2 2 2 2 22-8
3-5White-throated Spadebill (4)
Yellowish Flycatcher (3)
Long-tailed Manakin (10)
Rufous-and-white Wren (11)
Gray-breasted Wood-Wren (11)
Black-faced Solitaire (5)
Slate-throated Redstart (12)
Collared Redstart (12)
Three-striped Warbler (5)
Buff-mmped Warbler (3)
Common Bush-Tanager (3)
Olive Tanager (3)
Slaty Flowerpiercer (3)
White-eared Ground-Sparrow (13)Plain Wren (12)
Yellow-throated Euphonia (18)
Yellow-faced Grassquit (3)
Eastern Meadowlark (3)2
2
2
2-4
2
2-4
2-3
2-3
2 2 2 2 2 2 33-5
2-3
3aSources are as follows: (1) McDonald and Winnett-Murray 1989; (2) Lyon and Fogden 1989; (3) B. Young, pers. obs.; (4) D. McDonald, pers.
obs.; (5) D. Wenny, pers. obs.; (6) Wheelwright, pers. obs.; (7) Wheelwright 1983; (8) Riley 1986; (9) Powell 1983; (10) McDonald 1993b; (11)
Winnett-Murray 1986; (12) Shopland 1985; (13) Winnett-Murray 1985; (14) C. Howell, pers. comm.; (15) Lawton and Guindon 1981; (16)
Lawton and Lawton 1985; (17) Young 1994b; (18) Sargent 1993.
bMore than one female may lay in a single nest.6.3.4. IncubationBecause of a lack of study, it is not possible to gener-
alize about incubation in the birds of Monteverde. For
all passerines studied in Monteverde, only females
incubate (Lawton and Lawton 1985, Shopland 1985,
Sargent 1993, Young 1993a), but no data on ancestral
passerines such as the furnariids or dendrocolaptids
exist. Both sexes incubate in most nonpasserines,
except for hummingbirds and wood-quail (Wheel-
wright 1983, Riley 1986, Lyon and Fogden 1989,
McDonald and Winnett-Murray 1989). In quetzals,
both sexes incubate but only the female sits on the
nest at night (Wheelwright 1983). Each member of a
Sunbittern pair incubates for two days during the first
portion of the incubation period, and one day during
the latter portion (Lyon and Fogden 1989).
Incubating Brown Jays exhibit one of the most
puzzling behaviors of any species in Monteverde.
Females sit on the nest and "whine" incessantly, be-
ginning before the first egg is laid and lasting through-
out the incubation period. This characteristic whine
is given only by incubating females and is audible at
least 100 m from the nest (Lawton and Guindon 1981).
Up to five females may incubate in a nest, and each
whines while on the nest (Lawton and Lawton 1985).This behavior makes Brown Jay nests extraordinarily
easy for biologists to find but apparently is not com-
pelling enough to predators to make the behavior
maladaptive. The call most likely has a social func-
tion, perhaps serving as communication between the
lone incubating female and her flock (Skutch 1960).
This explanation is supported by the observation that
females are four times more likely to whine when
other flock members are present within 50 m of the
nest (Lawton and Lawton 1985).6.3.5. Postfledging
Tropical birds are characterized by long postfledging
periods in which fledglings remain on their natal ter-
ritories and receive food and perhaps predator pro-
tection from their parents. Monteverde birds are no
exception; most fledglings remain with their parents
for a considerable time after fledging (Table 6.5).
House Wrens, with a postfledging period of 3 weeks
to 3 months, are a useful point of comparison be-
cause they breed both in the tropics and in the tem-
perate zone. Temperate-zone House Wrens remain
in their natal territories for only 12-13 days (Gross
1948).193 Birds