SHORT COMMUNICATIONS 
641 
in Montana. Each female laid two eggs and started 
incubating while feeding large young in a nearby nest, 
and each successfully Hedged young from both nesting 
attempts. Simultaneous multiple nests base been 
documented for five other hummingbird species that 
breed north of Mexico, suggesting the behavior is 
widespread in the family outside the tropics, factors 
that might allow rapid renesting in temperate species 
include young that begin to feed themselves within a 
week after Hedging, and longer day length that allows 
more time for females to forage than would be' available 
in the tropics. Received 5 February 2012 Accepted 2 
April 2012. 
Reports of female hummingbirds simulta¬ 
neously caring for eggs and young from 
successive nesting attempts date to the mid- 
1930s when Skutch (1935:258) watched a female 
White-eared Hummingbird (Hylnchuris leucotis) 
feed a fledgling between bouts of incubation at 
what he assumed was her second nest ol the 
season. Rapid multiple brooding has since been 
documented or strongly suspected for tit least 
nine other species, the successive attempts 
beginning soon after young from an earlier 
attempt have Hedged (Blue-throated Humming¬ 
bird |Lampontis clemenciae], Williamson 2000; 
Lucifer Hummingbird |Calothorax lucifer\. 
Scott 1994; Anna’s Hummingbird |Calypte 
cmim], Maender et al. 19%; Allen’s Humming¬ 
bird [Selasphorus sasin |, Pitelka 1951). oi 
overlapping when a female lays eggs and begins 
incubation while feeding large young at another 
nest (Broad-billed Hummingbird |Cynantlvis 
latirostris], Baltosser 1989; Ruby-throated Hum¬ 
mingbird Archilochus coluhri. s|, Nickcll 1948, 
Black-chinned Hummingbird \A. alexanclri\. 
Cogswell 1949; Costa’s Hummingbird I Calypte 
costae], Baltosser and Scott 1996; Broad-tailed 
Hummingbird [Selasphorus platycercm 1. Bailey 
1974). Females of some species in the first group 
may build a second nest while Iceding nestlings 
but have not been documented laying eggs until 
after the first brood has fledged (e.g.. Anna s 
Hummingbird, Scarfe and Finlay 2001; Allen s 
Hummingbird. Legg and Pitelka 1956). We 
provide the first report of overlap nesting in 
two other species, the Calliope Hummingbiid 
(Stellala calliope ) and Rufous Hummingbird 
{Selasphorus ru/us). The female laid a second 
clutch in each case and began incubating while 
provisioning large young in a nearby nest. We 
also consider the factors that enable some 
hummingbirds to initiate breeding attempts in 
rapid succession despite the challenges of 
uniparental care of altricial young. 
OBSERVATIONS 
On 3 July 2001, NB, GB, and John Vanderpoel 
were shown two Calliope Hummingbird nests in 
a rural backyard near Red Lodge. Montana. Each 
nest was in a quaking aspen (Populus tremu- 
Utides) ~2.7 m above ground; the nest trees were 
14 m apart. One nest contained two eggs and the 
other had two large nestlings that were ~1 week 
from fledging. They watched the nests for 4 hrs 
on 3 and 4 July and witnessed several instances 
in which the female incubated for -15 min at 
one nest and then disappeared from view tor 5- 
10 min before returning to feed the young in the 
other nest. The female at times flew directly to 
the nest with esgs and incubated after feeding 
young at the other nest, verifying she was the 
same parent that attended each nest. The home- 
owners later reported that two young fledged 
from each nest. 
On 27 June 2008, DAL found a Rufous 
Hummingbird nest with two eggs -1 m above 
ground in a Douglas-fir (Pseudotsuga menziesii) 
sapling near Seeley Lake, Montana. He later 
watched the female leave (he first nest and fly to a 
second nest -6 m above ground in a larger 
Douglas-fir 20 m from the first nest. The second 
nest contained one large nestling that was within 
1 week of Hedging. On 2 July. DAL. NB, and Bob 
Martinka watched and photographed the female as 
she fed the nestling at the high nest and then Hew 
directly to the low nest and incubated. The single 
young from the high nest disappeared (presum¬ 
ably fledged) a day or two later, and the two 
young that hatched at the low nest fledged in early 
August. 
DISCUSSION 
Successful multiple nesting attempts in rapid 
succession have been documented for at least 12 
species of hummingbirds whose breeding ranges 
occur wholly or partly north of the tropics. Two 
nests can be occupied simultaneously for seven of 
these species, one with large young, and the other 
with recently laid eggs. Overlap nesting probably 
occurs regularly in species tor which it has been 
observed and likely will be documented in other 
temperate hummingbird species. At least six 
species of strictly tropical hummingbirds are 
known to raise more than one brood per year 
(Schuchmann 1999). but overlap nesting has not 
