An Interspecific Foraging Association Between Nearctic-Neotropical Migrant Passerines in Bolivia

2007·2.1 MB·English

by  Rosalind B Renfrew

124 THE WILSON JOURNAL OF ORNITHOLOGY • VoL 119, No. 1, March 2007
Martin, T E. 2002. A new view ofavian life-history Publications of the Nuttall Ornithological Club.
evolution tested on an incubation paradox. Pro^ Number 10. Cambridge, Massachusetts, USA.
ceedings of the Royal Society of London. Series Skutch, A. F. 1976. Parentbirds andtheiryoung. Uni-
B 269:309-316. versity ofTexas Press, Austin, USA.
Martin, T. E., R. D. Bassar, S. K. Bassar, J. J. Fon- Stiles, E. W. 1979. Nest and eggs of the White-
taine, P. Lloyd, H. Mathewson, A. M. Niklison, browed Tapaculo (Scytalopus superciliaris). Con-
AND A. Chalfoun. 2006. Life history andecolog- dor 81:208.
ical correlates ofgeographic variation in egg and Whitney, B. M. 1994. A new Scytalopus tapaculo
clutch mass among passerine species. Evolution (Rhinocryptidae) fromBoliva, with notesonother
60:390-398. Bolivian members ofthe genus and themagellan-
ScLATER, P. L. AND O. Salvin. 1879. On the birdscol- icus complex. Wilson Bulletin 106:585-614.
lected by the late Mr. T. K. Salmon in the state of Van Noordwijk, A. J., L. P. C. Keizer,J. H. vanBal-
Antioquia, United States of Columbia. Proceed- EN, AND W. ScHRLOO. 1981. Genetic variation in
ings of the Zoological Society of London 1879: egg dimensions in a population of Great Tit. Ge-
486-550. netica 55:221-232.
Sick, H. 1993. Birds in Brazil: a natural history. Young, B. E. and W. Zuchowski. 2003. First descrip-
Princeton University Press, Princeton, New Jer- tion of the nest of the Silvery-fronted Tapaculo
sey, USA. {Scytalopus argentifrons). Wilson Bulletin 115:
Skutch, a. E 1972. Studies oftropical Americanbirds. 91-93.
The Wilson Journal ofOrnithology 119(1):124-126, 2007
An Interspecific Foraging Association Between Nearctic-Neotropical
Migrant Passerines in Bolivia
Rosalind B. Renfrew'
—
ABSTRACT I present the firstpublishedrecordof On 1 1 February 2005 from 0900 to 1000
a foraging association between Nearctic-neotropical hrs EST in San Juan, depto. Santa Cruz, Bo-
migrant bird species during the austral summer in livia, ~100 km northwest of the city of Santa
rSuosuttihca)AmaenrdicCal.iffI Sowbaslelrvoewds {BPaertnroScwhaellildoownsp{yHrirrhuonnod-o Cruz, I observed a flock of —1,000 Bobolinks
ta) in February 2005 repeatedly foraging on aerial in- (Dolichonyx oryzivorous) foraging in soybean
sects flushed by flocks of Bobolinks {Dolichonyx ory- (Glycine max) fields. This large aggregation
zivorous) settling onto soybean plants (Glycine max). consisted of a series of smaller (30—400 in-
Additional observations would be needed to distin- dividuals) flocks that moved across the field
guish this behavior between an opportunistic associa- by landing in the soybeans for 15—60 sec, lift-
tion and a commensal relationship. Received 25 No- ing to 1-3 m above the soybeans, flying 25-
vember 2005. Accepted 28 July 2006.
50 m, landing again, and repeating this pat-
tern. After each landing, —10-30 Barn Swal-
Foraging associations assumed to be com- lows (Hirundo rustica) and 0-5 Cliff Swal-
lows (Petrochelidon pyrrhonota) captured
mensal between passerine species have been
dHeisncori1b9e9d8)wiatnhdinbemtiwxeeedn nspoenc-ifelsockfiloncgksspe(ec.ige.s, aaegriinagl 1i-ns5ecmtsabaobvoevethtehesoByobbeoalnicnaknoflpoyckf,orfo5r--
(e.g., Willis 1972, Maxson and Maxson 1981, 10 sec. During two subsequent walking tran-
Robbins 1981). Here, I report the first docu- sects (400 m), perpendicular to and intersect-
mentation of a foraging association between ing the flight path of the Bobolink flocks, I
two flocking Nearctic-neotropical migrant flushed Pyralid moths (Omiodes indicata Fa-
species during the austral summer. bricius) with every step. The other insect spe-
cies that flushed above the canopy, the adult
sto'cVkeRrdm.o,nPt. OIn.stBitouxte1o2f81N,atQuureaclheScei,enVcTe,065506559,WUoSoAd;- gsteamgmeatoafltihse Hvieilbvneetrb)e,anwacastenrpoitllaabru(nAdnatnitc.arsNioa
e-mail: [email protected] other insect species were observed flying
SHORT COMMUNICATIONS 125
above the soybean canopy. The insect fauna spent foraging may be higher (increased suc-
on soybean leaves appeared to be species-poor cess rate, Kushlan 1978).
and dominated by Pyralid moths, with species This association was not sustained over
of Coleoptera and Homoptera occasionally time. On seven subsequent dates over 2
noted. weeks, I observed monospecific flocks of
The “following” behavior I observed is Bobolinks using the same soybean field in the
frequently used by swallows, which are absence of swallows. On one of these dates.
known to follow mammals, birds, humans, Bobolink flocks were also observed in two
and farm equipment that flush prey. In some soybean fields ~3 km away, but swallows
cases, concentrations ofanimals serve as cues were not seen over or adjacent to the fields. I
to swallows that indicate local concentrations also observed swallows foraging over soybean
of food resources (Brown and Brown 1995, fields in the absence of Bobolinks.
1999). Once a few individual swallows locate The association reported may occur sporad-
a food source, they may serve to attract more ically in South American soybean fields when
swallows, known as “local enhancement” Bobolink and swallow distributions overlap
(Brown 1988). My observation of swallows spatially and temporally. Conditions under
feeding on lepidopterans is unusual, as lepi- which this phenomenon may occur in soybean
dopterans have been previously reported as fields must include (1) caterpillars consumed
comprising only a small fraction ofthe diet of by Bobolinks are available (e.g., after emer-
Cliff and Barn swallows (Beal 1918). How- gence and prior to application ofinsecticides),
ever, diet forthese opportunistic feeders varies (2) flying insects preferred by swallows are
depending on availability of prey items available, and (3) Bobolink flocks are suffi-
(Brown and Brown 1995, 1999). ciently large to flush prey in quantities that
The association between the three species, enable swallows to increase their foraging ef-
ficiency. Swallows may opportunistically use
if observed on a regular basis, could be an
example of commensal insectivory, whereby a “following” strategy to increase their for-
aging efficiency in different habitats with dif-
the swallows increase their foraging efficien-
ferent beater species in South America.
cy, while Bobolink foraging efficiency is un-
altered. Bobolinks are not known to forage on ACKNOWLEDGMENTS
aerial insects and were not observed feeding
above the soybean canopy. They were eating I thank A. M. Saavedra for her priceless assistance
in the field and the Museo de Historia Natural Noel
caterpillars on the soybean leaves (RBR, pers. Kempff Mercado for providing logistical and admin-
obs.), indicating they were not competing with istrative support in Bolivia. Dr. D. W. Winkler and C.
swallows for food resources. I did not observe C. Rimmer provided helpful comments on the manu-
interspecific aggression or other direct inter- script. I am grateful to Michael Sabourin and Dr. Alma
actions between the Bobolinks and swallows, Solis (Smithsonian) for identifying insects. I thank the
anonymous referees for their suggestions and com-
suggesting the swallows were not interfering ments that improved this manuscript.
with or otherwise altering Bobolink activity.
There are two ways that swallows might be LITERATURE CITED
increasing their foraging efficiency by follow- Beal, F. E. L. 1918. Food habits of the swallows, a
ing Bobolinks. However, I did not measure family of valuable native birds. U.S. Department
swallow foraging efficiency with, versus with- of Agriculture Bulletin 619.
out, Bobolinks as “beaters” (Rand 1954). Brown, C. R. 1988. Social foraging in CliffSwallows:
Bobolink flock activity appeared to invariably local enhancement, risk sensitivity, competition
and the avoidance ofpredators. Animal Behavior
increase the number of prey flying per unit 36:780-792.
area (prey density), and swallows may have Brown, C. R. and M. B. Brown. 1995. CliffSwallow
had a greater chance of locating prey, result- {Petrochelidon pyrrhonota). The birds of North
ing in more capture attempts perforaging bout America. Number 149.
or per unit time (increased feeding rate. Brown, C. R. and M. B. Brown. 1999. Barn Swallow
Brown 1988). Alternatively, when insects are N(Huimrbuenrdo45r2u.stica). The birds of North America.
forced to fly upon being flushed, the propor- Hino, T. 1998. Mutualistic and commensal organiza-
tion of successful capture attempts per time tion of avian mixed-species foraging flocks in a
126 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 119, No. 1, March 2007
forest of western Madagascar. Journal of Avian Rand, A. L. 1954. Social feeding behavior of birds.
Biology 29:17-24. Fieldiana-Zoology 36:1-71.
Kushlan,J. a. 1978. Commensalism inthe Little Blue Robbins, M. B. 1981. Two cases of commensal feed-
Heron. Auk 95:677-681. ing between passerines. Wilson Bulletin 93:391-
Maxson, J. anda. D. Maxson. 1981. Commensalfor- 392.
aging between Hairy and Pileated woodpeckers. Willis, E. O. 1972. The behaviorofSpotted Antbirds.
Journal of Field Ornithology 52:62-63. Ornithological Monographs 10.
The Wilson Journal ofOrnithology 1 19(1):126-128, 2007
Interspecific Egg-dumping by a Violet-green Swallow in an Active
Western Bluebird Nest
Danika Kleiber,' ^’^ Jenne Turner,'’"* Amber E. Budden,’’*^ and Janis L. Dickinson‘s^
—
ABSTRACT. We observed a Violet-green Swal- olet-green Swallow {Tachycineta thalassina)
low (Tachycineta thalassina) laying an egg in an ac- laying an egg in an active Western Bluebird
tive Western Bluebird (Sialia mexicana) nest. The {Sialia mexicana) nest containing nine-day-
Western Bluebird male and not the female, was ag-
gressive to the Violet-green Swallow but the swallow old nestlings at Hastings Natural History Res-
remained to lay the egg. This is the first documented ervation, Carmel Valley, California (36° 22' N,
incidence of which we are aware involving altricial 121° 34' W). Nest boxes have been monitored
interspecific egg-laying during the nestling phase. We at Hastings and nearby ranches as part of a
suggest the timing of this event was more consistent long-term study of Western Bluebirds since
with incidental egg deposition, or egg-dumping, than 1983 (Dickinson et al. 1996). Western Blue-
brood parasitism or nest usurpation. Received 13 De-
cember 2005. Accepted 24 July 2006. birds are the primary box-nesting species at
this study site, but other secondary cavity
nesters use nest boxes at lower frequencies,
including Ash-throated Flycatchers {Myiar-
Observations of birds laying eggs in nests chiis cinerascens). Oak Titmice {Baeolophiis
of other species are of interest because this inornatns). House Wrens {Troglodytesaedon),
behavior, when timed appropriately and di- Bewick’s Wren {Thryomanes hewickii) and
rected at nests where parents fail to recognize Violet-green Swallows (Table 1).
foreign eggs and offspring, may be the start- We conducted a study of parental feeding
ing point for evolution of interspecihc brood behaviors during spring 2005 using video to
parasitism. Other explanations for this behav- identify patterns of resource allocation within
ior are nest usurpation and egg-dumping,
which is the deposition of an egg into another
species’ nest without any specific adaptive
function. We collected video footage of a Vi- TABLE 1. Frequency of nest box use by second-
ary cavity-nesting species at Hastings Natural History
Reservation, Carmel Valley, California, from 1983 to
' Hastings Natural History Reservation, 38601 E. 2004.
Carmel Valley Rd., Carmel Valley, CA 93924, USA.
- University of British Columbia, Department of Species Nests(/!) Totaluse(%)
Forest Sciences, Forest Sciences Centre, 2424 Main
Mall, Vancouver, BC V6T 1Z4, Canada. Western Bluebird 1,860 69
1420Walnut St., Ste. 650, Philadelphia, PA 19102, OAsahk-tThirtomaotuedseFlycatcher 220984 118
USA.
House Wren 175 7
Department ofZoology, University ofToronto, 25
Harbord St., Toronto, ON M5S 3G5, Canada. VBieowliectk-’gsreWenreSnwallow 1222 <15
Cornell Laboratory ofOrnithology. 159 Sapsucker
Woods Rd., Ithaca, NY 14850, USA. Total nesting attempts (at least
one egg) 2,661 100
^Corresponding author; e-mail: [email protected]