The Wilson Journal of Ornithology 124 ( 3 ): 581 - 588 , 2012 
BIOLOGY OF INVASIVE MONK PARAKEETS IN SOUTH FLORIDA 
MICHAEL L. AVERY. 14 ERIC A. TILLMAN. 1 KANDY L. KEACHER.' 
JOHN E. ARNETT. 23 AND KELLI J. LUNDY' 
ABSTRACT.—Monk Parakeets ( Mxiop&itta monachus) have been m Honda lor -40 >rs ha\ong^ been 
thousands for the pet trade. This conspicuous, charismatic spec.es ■> now Widely and 
about its population biology outside South‘ body sue and aspects of reproductive 
collections by uultty company personnel in 2003/2004 and J«>6/-00 t tQ the mortachus 
biology and primary molt. Body measurements confirm Monk nf females exceeded that of males 
-ubspectes. Adult males averaged 15 to 3.5% larger than females, but the 
dunng March-May, the period of egg development. The M4u» 5.6 for 
spnng with fledglings first appearing in the second week o Arnett c ^ f ^ e J amined K J K replacing primary 
multiple-entry nests compared to 4.9 for single-entry nests. Over 94 * ot the adulto we exam n R ^ ^ jn 
others during June-August. The extent and timing of breeding and molt in south _ ; - characteristic of 
South America, although offset by -6 months. Monk Parakeets ,n south Honda e arn a Received , 
the ancestral population, bu, their flexible behavior enables them to adapt and thnve in new envrronments. 
Savember 2011. Accepted 3 March 2012. 
The Monk Parakeet (.Myiopsilta monachus) is 
native to South America, occurring from central 
Bolivia and southern Brazil south to central 
Argentina (Forshaw 1989). The species has become 
established in the mainland United States. Puerto 
Rico, Bahamas. West Indies. England. Belgium, 
Italy, Spain. Israel, and elsewhere through acciden¬ 
tal and purposeful introductions (Spreycr and 
Bucher 1998). The species first became established 
in the United Stales during the 1960s. The Monk 
Parakeet in Florida was first recorded breeding in 
Miami in 1969 and has been firmly established 
since the early 1970s (Owre 1974). 
The U.S. Fish and Wildlife Service initiated a 
naiionwide control and removal program in the 
early 1970s based on the species' reputation as an 
agricultural pest in South America. This program 
ended in 1975 and reduced the existing population 
by approximately one half (Neidermyer and 
Hickey 1977). The Monk Parakeet has thrived 
since 1975. however, in the USA and has become 
an urban/suburban species with no obvious factor 
limiting population growth. Monk Parakeets ate 
unique among psitlacines as they use sticks and 
twigs to construct bulky nests which house from 
'U.S. Department of Agriculture. Wildlife Services. 
National Wildlife Research Center, Florida Field Station. 
2820 East University Avenue. Gainesville. FL 32641.1 SA. 
'Department of Wildlife Ecology and Conservation. 
University of Florida, Gainesville. FL 32611. USA. 
5 Current address: 56th Range Management Office. Luke 
Air Force Base. AZ 85309. USA. 
4 Corresponding author; e-mail: 
michael.l.avery@aphis.usda.gov 
one to many individual nesting chambers (Spreyet 
and Bucher 1998). Parakeets in south Florida 
build nests principally on man-made structures 
such as stadium light poles, cell towers, and 
electric utility facilities (Newman et al. 2008). 
They exploit backyard bird feeders and non-native 
ornamental plants for food. Adverse effects of 
predation, diseases, and parasites to Monk Para¬ 
keets have not been documented in the USA. 
Aspects of Monk Parakeet natural history have 
been well-documented in its native range (c.g., 
Navarro and Bucher 1990. Navarro et al. 1992a. 
Martin and Bucher 1993. Eberhard 1998). Nest- 
site selection (Burger and Gochfeld 2000. Pranty 
9009) food habits (Hyman and Pruett-Jones 1995. 
South and Pruett-Jones 2000). population growth 
(Van Bael and Pruett-Jones 1996). nestling 
growth and development (Caccamise 1980). and 
population genetics <Russello et al. 2008. Gon¬ 
salves da Silva et al. 2010) have been studied m 
the USA. but other basic life history characteris¬ 
tics have not been quantified. We examined Monk 
Parakeets from south Florida to document their 
size, reproductive biology, and primary molt. Wc 
assessed variation between males and females and 
among seasons in these characteristics; the first 
•analysis of a Monk Parakeet population outside its 
native range. 
METHODS 
Sources of Birds.— We obtained birds at two 
different times. Personnel with Florida Power and 
Light Company removed 335 nests from distri¬ 
bution poles in Miami-Dade and Broward coun- 
581 
