Prothonotary Warbler (Protonotaria citrea)
Matt Gould
Status: Special Concern (MNFI)
Magee Marsh Wildlife Area, Ottawa Co., OH.
6/18/2009 © Darlene Friedman
This species sponsored by Ray Adams.
(Click to view a comparison of Atlas I to II)
Every spring the rivers of the southern Lower
Peninsula come alive with the loud, ringing
“tweet, tweet, tweet, tweet” song of the
Prothonotary Warbler. The Prothonotary
Warbler, formerly known as the golden swamp
warbler, is found in wooded bottomlands along
rivers and streams. Distinguished by its bright
yellow-orange head and breast and blue-gray
wings and tail, the Prothonotary Warbler is a
stunning sight to behold.
The breeding range for this species is
concentrated mostly in the southeastern United
States with Michigan, New York and southern
Ontario representing its northernmost range, and
Texas, Nebraska, and Oklahoma forming the
western boundary of its breeding range. During
the winter, Prothonotary Warblers migrate to
Central and South America where they prefer
mangrove forests.
Distribution
The Prothonotary Warbler has remained a
constant inhabitant of the southern LP since
MBBA I. Of the 17 confirmed reports in MBBA
II, the majority came from Berrien County
(three confirmed) north to Van Buren and
Allegan counties, and east to Kalamazoo
County (two confirmed in each). Wayne County
was the farthest east block with a confirmed
record, while Muskegon, Gratiot, and Saginaw
counties were the northernmost confirmed
records in the state. The northernmost record for
the species was a possible from Antrim County.
Several counties with confirmed breeding
records from MBBA I failed to have confirmed
records in MBBA II (Ottawa, Calhoun, Clinton,
Oakland, Branch and Cass). Wayne County was
the only county to have confirmed breeding
during MBBA II and not MBBA I. The
distribution of Prothonotary Warblers has
remained almost the same since MBBA I. The
SLP continues to have the densest
concentrations of this species since it was found
in every county in the southwestern part of the
state during both Atlas surveys.
Breeding Biology
The Prothonotary Warbler is one of only two
North American warblers to nest in cavities,
sharing this unique behavior with the western
species, Lucy’s Warbler (Oriothlypis luciae)
(Morse 1989). . Prothonotary Warblers often
construct their nests in old Downy Woodpecker
holes, but will use any other natural cavity in a
dead snag or branch of a live tree (Petit 1999).
The species is also partial to nest boxes placed
in suitable habitat and will readily use them. It
© 2011 Kalamazoo Nature Center
Prothonotary Warbler (Protonotaria citrea)
Status: Special Concern (MNFI)
is almost always found nesting above or near
standing water (Petit 1999). The nest itself is
comprised of two different substrates. The cup
is constructed of dry material, grasses, leaves
and rootlets, which are placed upon a thick,
moist bed of bryophytes, mosses and liverworts
(Blem and Blem 1994). On average the clutch
size for this species is three to seven eggs. In
Michigan the average clutch size was
approximately five eggs (Walkinshaw 1941).
Fledging for Prothonotary young occurs at 1011 days of age. Studies have shown that site
fidelity in Prothonotary Warblers increases with
the number of broods that are produced (Hoover
2003). Individuals benefit from returning to
territories that produced two or more broods and
also from abandoning territories that produced
zero broods (Hoover 2003). Parasitism is also a
concern for Prothonotary Warblers. Brownheaded Cowbirds have been observed
parasitizing Prothonotary Warbler nests more
frequently than other cavity nesting species
(Petit 1991). It has been observed that the
impact of parasitism on warblers is low as the
females will abandon the nest after it has been
parasitized. In many cases though, females will
accept the cowbird eggs if no other suitable
nesting sites are available within their territory
(Petit 1991).
Abundance and Population Trends
Throughout the southern LP, there was a slight
decline in the number of townships that reported
Prothonotary Warblers during MBBA II
compared to MBBA I. In the northern LP, three
townships
reported
possible
breeding
Prothonotary Warblers during MBBA II
compared to no reports at all from the northern
LP during MBBA I. In the southern LP, 38
townships reported possible breeding during
MBBA I compared to 29 during MBBA II.
Sixteen townships reported probable breeding
birds which was consistent between the two
surveys. confirmed breeding reports dropped
from 20 townships reporting during MBBA I to
only 15 townships during MBBA II
Matt Gould
(representing a 25% decline). One possible
reason for this small drop could be attributed to
the difficulty of surveying for this species.
Prothonotary Warbler habitat can be difficult to
survey on foot due to their preference for wet,
swampy areas. Float surveys are required for
much of the Prothonotary Warbler habitat in
Michigan. This method of surveying can be
limiting and therefore lead to birds being
overlooked by the surveyors.
Partners in Flight estimates the Michigan
population of Prothonotary Warbler to be
around 3,000 birds (PIF 2007). Prothonotary
Warbler populations are lower in the Upper
Midwest due to the fact that this area is the
northernmost extension of their breeding range.
BBS trends for Michigan since 1983 showed a
slight decline, whereas USFWS Region 3
showed a slight increase. However, neither of
these trends was significant. The only area in
the Great Lakes region that showed a significant
decline in population on Breeding Bird Surveys
was Ontario. Wisconsin, Illinois, Indiana and
Ohio all showed non-significant population
trends for the species (Sauer et al. 2008).
Conservation Needs
The Prothonotary Warbler remains a species of
special concern in Michigan. Partners in Flight
lists Prothonotary Warbler as a species of
conservation concern in the United States (PIF
2007). Degradation and destruction of habitat
had the greatest negative impact on the species
(Petit, 1999). While habitat degradation
negatively affects the nesting habitat of the
Prothonotary Warbler, recent studies have
shown that responsible timber harvest may not
have as detrimental an effect. Timber harvests
were shown to reduce the number of nest
cavities and increase the size of male territories,
but there was no increase in the number of nest
predations or brood parasitism in the study areas
(Cooper et al. 2009). Cooper et al. (2009)
theorize that the timing and extent of annual
flooding influences reproductive success more
© 2011 Kalamazoo Nature Center
Prothonotary Warbler (Protonotaria citrea)
Status: Special Concern (MNFI)
than timber harvest.
The protection of
bottomland hardwood forests and responsible
timber harvest practices are essential in the
conservation of this species. By protecting large
tracts of forest, the amount of competition with
other species is reduced, along with the density
of nest predators. Prothonotary Warblers have
also shown positive responses to artificial nest
cavities, such as nest boxes. Continued river
surveys are necessary to accurately evaluate the
status of this species in the SLP.
Matt Gould
Sauer, J.R., J.E. Hines, and J. Fallon. 2008.
The North American Breeding Bird Survey,
Results and Analysis 1966-2007. Version
5.15.2008.
USGS Patuxent Wildlife
Research Center. Laurel, Maryland, USA.
Walkinshaw, L.H. 1941. The Prothonotary
Warbler, A Comparison of Nesting
Conditions in Tennessee and Michigan.
Wilson Bulletin 53(1):3-19.
Suggested Citation
Literature Cited
Blem, C.R., and L.B. Blem.
1994.
Composition
and
Microclimate
of
Prothonotary Warbler Nests.
Auk
111(1):197-200.
Cooper, R.J., L.A. Wood, J.J. Gannon, and R.R.
Wilson. 2009. Effects of timber harvest and
other factors on a floodplain forest indicator
species,
the
Prothonotary
Warbler.
Wetlands 29(2):574-585.
Hoover, J.P. 2003. Decision rules for site
fidelity in a migratory bird, the Prothonotary
Warbler. Ecology 84(2):416–430.
Morse, D. H. 1989. American warblers: an
ecological and behavioral perspective.
Harvard University Press, Cambridge,
Massachusetts, USA.
Partners in Flight [PIF]. 2007. PIF Landbird
Population Estimates Database. Version
2004. Rocky Mountain Bird Observatory.
<http://www.rmbo.org/pif_db/laped/default.
aspx>. Accessed 4 November 2009.
Petit, L.J. 1991. Adaptive tolerance of cowbird
parasitism by prothonotary warblers: A
consequence of nest-site limitation? Animal
Behavior 41(3):425-432.
Petit, L.J.
1999.
Prothonotary Warbler
(Protonotaria citrea). Account 408 in A.
Poole and F. Gill, editors. The Birds of
North America.
The Birds of North
America, Inc., Philadelphia, Pennsylvania,
USA.
Gould, M.
2011.
Prothonotary Warbler
(Protonotaria citrea). in A.T. Chartier, J.J.
Baldy, and J.M. Brenneman, editors. The
Second Michigan Breeding Bird Atlas.
Kalamazoo Nature Center. Kalamazoo,
Michigan, USA. Accessed online at:
<www.mibirdatlas.org/Portals/12/MBA2010
/PROWaccount.pdf >.
© 2011 Kalamazoo Nature Center