Bird species occurring in rice fields and
surrounding habitats at Merin Lagoon
watershed, Uruguay
Ethel Rodríguez & Guadalupe Tiscornia
Dirección General de Servicios Agrícolas - Ministerio de Ganadería, Agricultura y Pesca
Avenida Millán 4703 - (12900) - Montevideo - Uruguay
[email protected]
Este documento puede citarse como sigue:
Rodríguez, E. y G. Tiscornia. 2008. Bird species occurring in rice fields and surrounding habitats at Merin Lagoon watershed,
Uruguay [en línea]. En de la Balze, V.M. y D.E. Blanco (eds.): Primer taller para la Conservación de Aves Playeras Migratorias en
Arroceras del Cono Sur. Wetlands International, Buenos Aires, Argentina <http://lac.wetlands.org>
Abstract
As part of a comprehensive study of bird pest
management in rice, we censused birds at four locations
in the Merin Lagoon rice-growing region of eastern
Uruguay. Study sites were randomly selected and
included six different habitat types: rice field (all stages),
grassland, irrigation canal (levees), forest, wetland and
wet meadow (pajonal). Study localities averaged 400 ha.
and we visited each location 13 times between March
1994 and February 1995 (624 total observation hours).
Rice habitat was the most used (more species seen
more frequently). In total we identified 121 bird species
representing 17 orders. Passerines represented 43% of
total. The Chestnut-capped Blackbird (Agelaius
ruficapillus) was the most common species, and was
often present in large flocks feeding on the rice crop.
71% of all species recorded breed in the study area.
Migratory species represented 15% of the total. Several
species classified as rare or endangered were also
recorded. The rice crop environment, including
surrounding habitats, represents a critical resource for
bird populations.
Introduction
Rice is the third most valuable export commodity of
Uruguay. Within the last 10 years, rice acreage has
been doubled and at present represents 145.400 ha
(Encuesta arrocera, zafra 2006-07). Most production
(73%) is concentrated in the eastern part of the country
(Rocha, Treinta y Tres and Cerro Largo Departments)
where the crop is planted in a wetland environment
modified for rice cultivation. This environment features
special ecological characteristics, is very rich in bird
species, and has much value for conservation.
The objective of this study performed in 1994-95 was to
determine which bird species occurred in rice crops and
1
surrounding habitats, and to determine their frequency
of occurrence on a monthly basis throughout the year 1.
Study area and methods
Study area
The study area comprises the Uruguayan part of Merin
Lagoon. The observation sites were randomly chosen
from a list of the rice companies within the zone. The
four chosen localities were: Río Branco (Cerro Largo
Department), “Arrozal 33” (Treinta y Tres), Cebollatí y
Chuy (both in Rocha) (Fig. 1).
We defined six habitat types, or environments (Fig. 2):
1) Rice: all of the different phenological stages from
sowing to harvest, and stubble.
2) Prairie, road borders: areas where rice is no longer
grown, that have been seeded or have been
naturally converted to grassland or pasture. Also
includes grassy borders along the roads and levees.
3) Irrigation canals and levees: irrigation canals and
ditches; an environment rich in aquatic vegetation,
aquatic vertebrates, and invertebrates.
4) Forest: natural forest (mostly Acacia sp., Eugenia
sp., Verberis sp., Allophylus sp.) or planted woods of
Eucalyptus sp.
5) Wetlands and estuary: flooded areas surrounding
the crops; areas not bigger than 4 acres in most
cases.
6) Wet meadows (Pajonal): areas represented by
Panicum sp. and Eryngium sp., generally of one acre
or even smaller between the rice crop and other
habitat types.
Project financed by National Institute for Agricultural Research (INIA), Ministry of Livestock, Agriculture and Fishing (M.G.A.P.), and
Rice Growers Association (A.C.A.)
1
Primer taller para la Conservación de Aves Playeras Migratorias en Arroceras del Cono Sur
Rio Branco
Arrozal 33
Cebollatí
Chuy
Figure 1. Satellite image showing the study area.
Results and discussion
In total, 121 species from 17 orders were identified (see
Annex 1). Passerines (order Passeriformes) represented
43% of the total. The overall frequency of occurrence
peaked in September, when the rice fields were in
stubble (Fig. 3). Overall, species occurrence was higher
in the rice field environment (Fig. 4).
Figure 2. Rice crop. In this picture we can almost see
the six habitat types (rice, prairie, irrigation canals,
forest, wetlands and wet meadows).
Methods
Bird observations were made between March 1994 and
February 1995, and each locality was visited 13 times.
The counts started at daylight and totaled 624
observation hours. At each locality, an average of 400
ha was covered by vehicle by using roads as sampling
transects (Bibby et al. 1993).
We identified bird species with binoculars, spotting
scope, or by vocalizations. For bird identifications we
followed Arballo & Cravino (2005). We tabulated the
observations by locality, date, bird species presence and
environment. We also noted that there were bird nests in
rice fields.
For each habitat type, we calculated the frequency of
occurrence of all the bird species by dividing the number
of times the species was detected by the total number of
visits to the habitat type. The frequency of occurrence of
each species in the environments gave us an idea of
how the species are using the different habitats.
2
Along the six habitat types, the 10 species most
frequently observed were Agelaius ruficapillus
(Chestnut-capped Blackbird), Furnarius rufus (Rufous
Hornero), Pitangus sulphuratus (Great Kiskadee), Circus
buffoni (Long-winged Harrier), Platalea ajaja (Roseate
Spoonbill), Myiopsitta monachus (Monk Parakeet),
Egretta thula (Snowy Egret), Anumbius annumbi
(Firewood-Gatherer), Ciconia maguari (Maguari Stork)
and Amazonetta brasiliensis (Brazilian Duck).
Within the rice field habitats, the species most frequently
observed was Agelaius ruficapillus which was recorded
on every visit and occurred in large flocks, having
therefore a substantial economic impact on the rice crop
(Rodríguez et al. 1998). Other common species were:
Circus buffoni (100%), Ciconia maguari (100%),
Phimosus infuscatus (Bare-faced Ibis) (92%), Egretta
alba (Great Egret) (85%), Egretta thula (85%), Plegadis
chihi (White-faced Ibis) (77%), Dendrocygna viduata
(White-faced Tree-Duck) (77%), Amazonetta brasiliensis
(77%), Furnarius rufus (77%), and Sicalis luteola
(Grassland Yellow-Finch) (77%).
Many of the species recorded are migratory species of
seasonal occurrence, and can be assigned to three
categories (Arballo & Cravino, op cit.): 1) non-nesting
summer visitors from the northern hemisphere, 2) winter
visitors from southern South America and 3) summernesting species.
Primer taller para la Conservación de Aves Playeras Migratorias en Arroceras del Cono Sur
60
50
Rice
Irrigation cannals
Prairie
Forest
Wetland
Wet meadows
40
30
20
10
2/
D
1/
D
12
/D
11
/S
dl
10
/P
9/
S
8/
S
7/
S
6/
S
5/
Sh
3/
Sd
4/
Sm
3/
Sm
0
month/rice phenological stage
Figure 3. Percentage of bird occurrence by habitat type and rice phenological stage at rice fields in Uruguay. Sm =
seed at milky stage, Sd = seed at dough stage, Sh = seed at hard stage, S = stubble, P = planting, Sdl = seed
development, D = development.
1) Non-nesting summer visitors: Mycteria americana
(Wood Stork), Pluvialis dominica (American Golden
Plover), Tringa flavipes (Lesser Yellowlegs), Tringa
solitaria (Solitary Sandpiper), Calidris melanotos
(Pectoral Sandpiper) and Hirundo rustica (Barn
Swallow).
2) Winter visitors from southern South America:
Charadrius modestus (Rufous-chested Dotterel),
Cinclodes fuscus (Bar-winged Cinclodes) and
Lessonia rufa (Rufous-backed Negrito).
3) Summer nesting species: Butorides striatus (Striated
Heron), Rostrhamus sociabilis (Everglade Kite),
Podager nacunda (Nacunda Nighthawk),
Phyroscephalus rubinus (Vermilion Flycatcher),
Tyrannus savana (Fork-tailed Flycatcher), Tyrannus
melancholicus (Tropical Kingbird), Phaeoprogne
tapera (Brown-chested Martin), Tachycineta
leucorrhoa (White-rumped Swallow) and
Notiochelidon cyanoleuca (Blue-and-White Swallow).
Some of the species recorded are considered rare or
scarce for Uruguay (Gore & Gepp 1978). These include
Botaurus pinnatus (Pinnated Bittern) with 31% of
occurrence inside the crops and 15% on banks;
Callonetta leucophrys (Ringed Teal) present throughout
the study and sometimes nesting in the area; Cathartes
burrovianus (Lesser Yellow-headed Vulture) with 38% of
occurrence in crops and 8% in grassland; Asthenes
hudsoni (Hudson’s Canastero) and Spartonoica
maluroides (Red-capped Wren-Spinetail). The latter two
species occurred in May in the rice field environment.
Species frecuency of occurence by habitat type
Forest
13%
Prairie
23%
Wetland
6%
Wet meadows
3%
Rice 42%
Irrigation cannals 13%
Figure 4. Percentage of species occurrence by habitat
type at rice fields in Uruguay.
Columbina talpacoti (Ruddy Ground-Dove), considered a
species of uncertain distribution (Gore & Gepp op cit.),
was observed regularly throughout the area, sometimes
in flocks of 10 to 15 individuals. Sporophila collaris
(Rusty-collared Seedeater), a species with irregular
movement patterns, was recorded year-round. Our
observations of these two last species confirm the
previous findings of Arballo (1990).
Other species categorized as scarce for the region but
present in rice habitat were: Circus cinereus (Cinereous
Harrier), Melanerpes candidus (White Woodpecker),
Anthus lutescens (Yellowish Pipit), Icterus cayanenesis
(Epaulet Oriole) and Serpophaga munda (White-bellied
Tyrannulet).
3
Primer taller para la Conservación de Aves Playeras Migratorias en Arroceras del Cono Sur
Of the 121 species observed during the study (Annex 1),
71% nests in many of the habitat types of the study
area. Those species recorded nesting in the rice field
habitat were: Gallinula Chloropus (Common Gallinule),
Agelaius ruficapillus, Tigrisoma linneatum (Rufescent
Tiger-Heron), Botaurus pinnatus, Dendrocygna bicolor
(Fulvous Tree-Duck), Dendrocygna viduata, Netta
peposaca (Rosy-billed Pochard) and Pardirallus
sanguinolentus (Plumbeous Rail).
Seven species of special concern for conservation
(according to the IUCN Red List of Threatened species)
were recorded. For example, Sporophila palustris
(Marsh Seedeater) which was found on wet meadows
(pajonales) is considered an Endangered species.
Agelaius flavus (Saffron-cowled Blackbird) and
Heteroxolmis dominicana (Black-and-White Monjita) are
classified as Vulnerable. Four others are considered
Near Threatened: Rhea americana (Greater Rhea),
Spartonoica maluroides, Limnoctites rectirostris
(Straight-billed Reedhaunter), found on wild bushes of
“caraguatal”, and Polystictus pectoralis (Bearded
Tachuri) recorded on the transition zone between wild
bushes and natural forest.
This information has been shared not only with the
scientific community (Temperate Rice Conference 1999,
Rodriguez & Arballo 1997, Rodriguez et al. 1998, 2001)
but also in outreach publications (Tiscornia & Rodriguez
2003).
These observations contribute to show how valuable is
the rice ecosystem (the rice crop itself and the
associated habitat types) in the diversity of the bird
community. Conservation planning for enhancing
biodiversity should incorporate the rice environment as
an integral component of the landscape. And if rice
agroecosystem management is done in a responsible
way it will contribute to preserve many bird species.
Acknowledgments
Authors are grateful to Mr. Eduardo Arballo and Ing.
Pablo Lopez for field work and bird identification, to
Angeles Camacho for laboratory assistance, to Mike
Avery for scientific and translation help, to the National
Institute for Agricultural Research, Rice Growers
Association (ACA) and Ministry of Livestock, Agriculture
and Fisheries for their financial support, and to rice
growers for having us on their fields.
4
References
Arballo, E. 1990. Nuevos registros para avifauna
uruguaya. El Hornero 13 (2):179-187.
Arballo, E. & J. Cravino. 2005. Aves del Uruguay.
Manual Ornitológico. Ed. Hemisferio Sur.
Montevideo, Uruguay. 466 pp.
Azpiroz, A. B. 2003. Aves del Uruguay. Lista e
introducción a su biología y conservación. Aves
Uruguay-GUPECA. Montevideo. 104 pp.
Bibby, J.C., N.C. Burgess & D.A. Hill. 1993. Bird Census
techniques.
(DIEA) Encuesta arrocera. Zafra 2006-07. Boletín
informativo. Estadísticas Agropecuarias.
http://www.mgap.gub.uy/diea/Encuestas/Se248/SE24
8_EncuestaArrocera0607.htm
Gore M.E. & A.R.M. Gepp. 1978. Las Aves del Uruguay.
Mosca Hnos., Montevideo.283 pp.
Rodríguez, E.N. & E.R. Arballo. 1997 Identificación de
especies de aves que ocurren en el cultivo de arroz
y ambientes aledaños en la cuenca de la Laguna
Merín, Uruguay. En: Silva, J.J.C., D.F. da Franco &
M.P. Cirne (eds.): I Reunión sobre o Passaro Preto
(Agelaius ruficapillus) e sua interacâo com a cultura
do arroz nos países de Mercosul, Pelotas (19-21
agosto 1997). Ministério da Agriculttura e do
Abastecimento, Pelotas, RS Brasil.
Rodríguez, E., P. López, A. Camacho & E. Arballo. 1998.
Manejo de Aves Plaga en el cultivo de arroz.
Publicaciones INIA. Serie Técnica No 96, 16 pp.
Rodríguez, E., V. Korenko & G. Tiscornia. 2001. Manejo
del Pájaro Negro Agelaius ruficapillus en el cultivo de
arroz. Instituto Nacional de Investigación Agropecuaria
(INIA). Serie Técnica FPTA INIA 05, 51 pp.
Tiscornia, G & E. Rodríguez. 2003. La rizofauna. Una
riqueza <<plus>>. Revista de la Asociación de
Cultivadores de Arroz. Nº 36: 44-48.
IUCN. 2007. Red List of Threatened species
(http://www.iucnredlist.org)
Primer taller para la Conservación de Aves Playeras Migratorias en Arroceras del Cono Sur
Annex 1
Bird species within the study area expressed by frequency of occurrence (percentage of field days in which a species
was found within a certain habitat type). N = 13, visits = 100%. Birds listed according to Azpiroz (2003).
Habitat type
Order/Species name
Rice
Irrigation
canals
Prairie
Forest
Wetland
Wet meadows
(pajonal)
62
0
15
0
8
0
31
0
31
8
0
0
0
54
0
0
0
0
Botaurus pinnatus
31
15
0
0
0
0
Tigrisoma lineatum
8
15
0
0
8
0
Nycticorax nycticorax
8
0
0
8
15
0
Bubulcus ibis
54
8
46
0
0
0
Syrigma sibilatrix
31
0
31
0
0
0
Butorides striatus
0
0
0
0
23
0
Egretta thula
85
54
8
0
15
0
Egretta alba
85
54
0
0
8
0
Ardea cocoi
23
46
0
0
0
0
Mycteria americana
46
15
8
0
8
0
Ciconia maguari
100
38
8
0
8
0
Theristicus caerulescens
38
0
15
0
0
0
Phimosus infuscatus
92
15
23
0
0
0
Plegadis chihi
77
23
8
8
23
0
Platalea ajaja
31
62
23
23
31
0
Dendrocygna bicolor
46
0
0
0
0
0
Dendrocygna viduata
77
0
8
0
8
0
Calloneta leucophrys
38
46
8
0
0
0
Amazonetta brasiliensis
77
62
15
0
0
0
Anas flavirostris
38
8
0
8
0
0
Anas georgica
23
31
0
0
0
0
Anas versicolor
23
15
0
0
15
0
Netta peposaca
31
8
0
0
0
0
Chauna torquata
69
0
15
0
8
0
Struthioniformes
Rhea americana
Tinamiformes
Nothura maculosa
Pelecaniformes
Phalacrocorax brasilianus
Ciconiiformes
Anseriformes
5
Primer taller para la Conservación de Aves Playeras Migratorias en Arroceras del Cono Sur
Habitat type
Order/Species name
Rice
Irrigation
canals
Prairie
Forest
Wetland
Wet meadows
(pajonal)
Cathartes aura
8
0
8
0
0
0
Cathartes burrovianus
38
0
8
0
0
0
Elanus leucurus
0
23
8
0
0
0
Rostrhamus sociabilis
23
54
23
8
0
0
Circus buffoni
100
0
31
0
31
31
Circus cinereus
23
0
15
0
0
8
Buteogallus meridionalis
8
0
0
0
0
0
Falconiformes
Rupornis magnirostris
0
0
23
23
0
0
Polyborus plancus
46
0
31
15
0
0
Milvago chimango
54
0
54
8
0
0
Falco sparverius
15
0
15
8
0
0
Falco femoralis
23
0
0
0
0
0
Aramus guarauna
15
46
0
0
0
0
Aramides ypecaha
0
15
15
15
15
31
Pardirallus sanguinolentus
23
0
0
0
0
0
Gallinula chloropus
38
0
0
0
8
0
Jacana jacana
0
8
0
0
8
0
Himantopus mexicanus
54
23
0
0
0
0
Vanellus chilensis
62
8
46
8
15
0
Pluvialis dominica
46
8
15
0
8
0
Charadrius collaris
8
0
8
0
0
0
Charadrius modestus
15
0
0
0
0
0
Tringa flavipes
15
0
0
0
0
0
Tringa solitaria
0
8
0
0
0
0
Gallinago paraguaiae
38
31
8
8
23
0
Calidris melanotos
8
0
0
0
8
0
Larus maculipennis
69
38
15
0
8
0
Columba maculosa
8
0
8
0
0
0
Columba picazuro
46
0
0
15
0
0
Zenaida auriculata
15
0
62
0
0
0
Columbina talpacoti
8
0
23
8
0
0
Columbina picui
31
0
54
15
0
0
Leptotila verreauxi
0
0
0
8
0
0
62
0
23
85
0
0
Gruiformes
Charadriiformes
Columbiformes
Psittaciformes
Myiopsitta monachus
6
Primer taller para la Conservación de Aves Playeras Migratorias en Arroceras del Cono Sur
Habitat type
Order/Species name
Rice
Irrigation
canals
Prairie
Forest
Wetland
Wet meadows
(pajonal)
31
0
8
31
0
0
8
15
46
0
0
0
23
0
8
0
0
0
Choroceryle amazona
0
23
0
0
0
0
Chloroceryle americana
0
31
0
0
0
0
Melanerpes candidus
0
0
0
8
0
0
Colaptes melanochloros
0
0
8
15
0
0
Colaptes campestris
8
0
8
23
0
0
Cinclodes fuscus
8
8
0
0
0
0
Furnarius rufus
77
0
92
54
0
0
Spartonoica maluroides
8
0
0
0
0
0
Cuculiformes
Guira guira
Strigiformes
Speotyto cunicularia
Caprimulgiformes
Podager nacunda
Coraciiformes
Picifomes
Passeriformes
Schoeniophylax phryganophila
0
0
0
8
0
0
Asthenes hudsoni
0
0
0
0
8
0
Phacellodomus striaticollis
0
0
0
0
0
23
Anumbius annumbi
23
0
62
69
0
8
Serpophaga munda
0
0
0
8
0
0
Serpophaga nigricans
0
8
8
0
0
0
Pyrocephalus rubinus
15
0
15
15
0
0
Xolmis cinerea
0
0
8
8
0
0
Xolmis irupero
15
0
46
0
0
0
Heteroxolmis dominicana
0
0
0
0
0
8
Lessonia rufa
0
0
8
0
0
0
Hymenops perspicillatus
0
0
0
0
8
0
Satrapa icterophrys
0
15
8
0
8
0
Machetornis rixosus
31
8
38
38
0
0
Pitangus sulphuratus
54
38
69
46
0
0
Tyrannus melancholicus
0
0
0
0
8
0
Tyrannus savana
31
0
31
31
0
0
Tachycineta leucorrhoa
62
0
46
0
0
0
Progne tapera
23
0
15
8
0
0
Notiochelidon cyanoleuca
38
0
0
8
0
0
Hirundo rustica
8
8
0
0
0
0
Anthus correndera
38
0
0
0
0
0
7
Primer taller para la Conservación de Aves Playeras Migratorias en Arroceras del Cono Sur
Habitat type
Order/Species name
8
Rice
Irrigation
canals
Prairie
Forest
Wetland
Wet meadows
(pajonal)
Anthus hellmayri
8
0
8
0
0
0
Anthus lutescens
15
8
0
0
0
0
Troglodytes aedon
8
0
23
38
8
0
Turdus amaurochalinus
8
0
0
8
0
0
Turdus rufiventris
0
0
0
8
0
0
Polioptila dumicola
0
0
0
8
0
0
Zonotrichia capensis
8
0
31
15
0
0
Ammodramus humeralis
0
0
23
0
0
0
Poospiza nigrorufa
8
0
8
8
0
0
Sicalis flaveola
31
0
54
54
0
0
Sicalis luteola
77
0
31
15
0
0
Embernagra platensis
0
0
0
0
0
15
Sporophila collaris
0
0
0
0
8
8
Paroaria coronata
46
0
23
38
8
0
Icterus cayanensis
0
0
0
8
0
0
Xanthopsar flavus
8
0
0
8
0
8
Agelaius ruficapillus
100
23
62
69
0
15
Agelaius thilius
15
0
0
0
15
15
Sturnella superciliaris
54
0
15
0
8
0
Pseudoleistes virescens
38
0
31
15
8
15
Amblyramphus holosericeus
8
0
0
0
15
8
Molothrus badius
46
0
23
31
15
0
Molothrus bonariensis
23
0
62
15
0
0
Molothrus rufoaxillaris
31
0
0
8
0
0
Carduelis carduelis
0
0
8
0
0
0
Carduelis magellanica
0
0
31
0
0
0
Passer domesticus
15
0
23
8
0
0