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BIOLOGICAL AND ECOTOXICOLOGICAL CHARACTERISTICS OF TERRESTRIAL VERTEBRATE SPECIES RESIDING IN ESTUARIES

Saltmarsh Sparrow Saltmarsh sparrow
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Saltmarsh Map

Birds of North American Online, Cornell Lab of Ornitholgy

Biological Characteristics

Species Ammodramus caudacutus is a small sparrow approximately 11-13 cm in length with an average weight of 14-21 grams (Greenlaw and Rising, 1994).  Two subspecies exist (A.c. diverus, A.c. caudacutus, and the English name has recently been revised from Saltmarsh Sharp-tailed Sparrow to Saltmarsh Sparrow (Chesser et al., 2009).  Field marks include a broad orange malar stripe and eyeline which are very distinct, gray ear coverts, gray nape, and bill is bi-colored.  Their upper breast is lightly streaked and flanks are bright buff colored and streaked (Greenlaw and Rising, 1994).
Status in Estuaries Saltmarsh sparrows have a polygamous mating strategy, are promiscuous and only females select the nest site, build the nest, and care for the young (Greenlaw and Rising, 1994).  Sparrows are found breeding in wet meadows, freshwater marshes, and salt marshes. Clutch size is approximately 3-5 buff eggs.  Nests are approximately 5-10 cm above ground and conspicuous in marsh grasses (i.e., in salt marshes sparrows nest in S. alterniflora, S. patens, and cordgrassspecies) and thatch or dead plant material from the previous year (Deragon, 1988).  Saltmarsh sparrows are susceptible to high predation and flood events.
Abundance and Range Three distinct breeding populations make up the species.  Two occurring in marshes along the North Atlantic coast, and one in the interior Canada and south through North Dakota.  Based on crude range estimates numbers are between 50,000 to 100,000 with population trends decreasing (Birdlife International, 2010).
Site Fidelity Species exhibit strong nest site fidelity (Greenlaw and Rising, 1994).  In New Jersey about 55% of the birds banded returned to the same marsh (Worth, 1972).
Ease of Census Moderate. In areas where breeding populations are abundant this species is easy to find, but can be harder to detect during the winter season.
Feeding Habits Saltmarsh sparrows forage by gleaning prey off wetland vegetation and probing in ground and water surfaces (Post and Greenlaw, 1982).  They feed on adult and larval insects, spiders, amphipods, and seeds of plants (Greenlaw and Rising, 1994).
Conservation Status Saltmarsh sparrows are threatened by multiple factors (habitat degradation, invasion of exotic species, sediment erosion, sea-level rise, and contaminants).  In the Canadian Maritimes, available breeding habitat has been reduced by 50% during last 300 years by diking and draining of habitat (Erksine, 1992).  The U.S. Fish and Wildlife Service Partners in Flight Program, has established a national level conservation status for saltmarsh sparrows, ranking the species as a bird of conservation concern (USFWS, 2010). 

Saltmarsh Sparrow Contaminant Exposure Data

I.

Organochlorine Contaminants

1.

Saltmarsh sparrow eggs that failed to hatch were collected from nests at Parker River National Wildlife Refuge (NWR), Maine, 2007.  The concentration (µg/g wet weight) of p,p´- DDE in 19 eggs ranged from 0.044 - 0.300, oxychlordane  levels in 13 eggs ranged from 0.006 - 0.330, mirex concentration analyzed in 1 egg was 0.028, heptachlor epoxide in 1 egg was 0.004, gamma chlordane in 6 eggs ranged from 0.004 - 0.010,  gamma BHC in 4 eggs ranged from 0.003 - 0.008, dieldrin concentrations analyzed in 10 eggs ranged from 0.005 - 0.010, and beta BHC concentrations in 18 eggs ranged from 0.004 - 0.008.  PCB’s were detected in the greatest concentrations (range 0.180 - 0.710), however still below levels reported to have detrimental effects (Lane et al. 2008).

II.

Cholinesterase-Inhibiting Pesticides

 

No direct exposure data available

III.

Trace Elements, Metals and Metalloids

1.

Blood samples were collected from adult saltmarsh sparrows in 5 marshes along the Maine coast, June - August 2001, and analyzed for total Hg µg/g (ww) (Shriver et al. 2006).  There were no differences in blood Hg concentrations between males and females.  At the Weskeag Marsh, blood Hg concentrations from 5 sparrows averaged 0.626 (range 0.414 - 1.170).  At Popham Marsh, the average concentration from 6 sparrows was 0.867 (range 0.773 - 1.150).  At Scarborough Marsh, the average concentration from 21 sparrows was 0.562 (range 0.342 - 1.015).  At the Ogunquit Marsh, the average concentration for 10 sparrows was 0.809 (range 0.625 - 1.260).  At the York marsh, the average concentration from 10 sparrows was 0.751 (range 0.490 - 0.921).  When data from all 5 marshes were combined, the average for 53 sparrows was 0.690 with a range of 0.342 - 1.260.  It is suggested that sparrows are ingesting Hg from prey items and are ideal species to use as an index to the availability of MeHg in salt marsh habitats.  Saltmarsh sparrows had nearly twice the concentration of Hg than the closely related Nelson Sparrow (Ammodramus nelsoni) which was also sampled at the sites (Shriver et al. 2006).

2.

Saltmarsh sparrow blood was analyzed for Hg concentrations from multiple marshes along the mid Atlantic coast (2004 – 2007).  Blood Hg concentrations are expressed in µg/g (ww) and the average, range, and sample size (N) are reported below for all 4 years (Lang et al. 2008).

a.

Data From 2004.
Mercury blood concentrations in Connecticut at Hammock River Marsh averaged 0.23 (range 0.18 - 0.24, N=6), and at Stewart B. McKinney averaged 0.54 (range 0.39 - 0.73, N=15).  In Maine, Rachel Carson National Wildlife Refuge (NWR) Spurwink Marsh blood concentrations averaged 0.45 (range 0.26 - 0.60, N=10), Scarborough Marsh Wildlife Management Area (WMA) averaged 0.47 (range 0.23 - 0.82, N=15), Rachel Carson NWR at Goosefare Brook averaged 0.50 (range 0.32 - 0.75, N=13), Rachel Carson NWR Granite Point averaged 0.54 (range 0.46 - 0.66, N=3), Rachel Carson NWR in Furbish Marsh averaged 0.56 (ranged 0.33 - 0.69, N=14), and Rachel Carson NWR at the Little River Marsh averaged 0.74 (range 0.64 - 0.84, N=7).  In Rhode Island, Ninigret NWR Sachuest Marsh blood concentrations averaged 0.72 (range 0.54 - 0.87, N=9), and Ninigret NWR Chafee Marsh averaged 1.08 (range 0.86 - 1.36, N=6).  In Massachusetts at Parker River NWR, blood concentrations averaged 1.09 (range 0.67-1.68, N=10).  The lowest blood Hg concentrations were detected in sparrows from Connecticut and the greatest were from sites in Massachusetts (Lane et al. 2006, 2008).

b.

Data From 2005.
In Maine, Libby River Scarborough Marsh blood concentrations averaged 0.31 (range 0.28 - 0.42, N=7), Nonesuch River Scarborough Marsh averaged 0.45 (range 0.39 - 0.52, N=2), Rachel Carson NWR Spurwink Marsh averaged 0.61 (ranged 0.40 - 0.87, N=13), and at the Rachel Carson NWR Furbish Marsh site averaged 0.76 (range 0.47 - 1.44, N=21).  In Connecticut, Stewart B. McKinney NWR Salt Meadow Unit blood concentrations averaged 0.61 (range from 0.44 - 0.96, N=10).  In Rhode Island, Ninigret NWR Chafee Marsh blood concentrations averaged 0.79 (range 0.41 - 1.17, N=15).  In Massachusetts Parker River NWR, blood concentrations averaged 1.24 (range 0.81 - 2.22, N=15).  The lowest blood Hg concentrations were detected in sparrows from Stewart B. McKinney NWR and Rachel Carson NWR, with Parker River NWR having the greatest concentrations (Lane et al. 2006, 2008).

c.

Data from 2006.
In Maine at Rachel Carson NWR Furbish Marsh, average concentrations were 0.73 and ranged from 0.58 - 0.95 (N=16), and at Rachel Carson NWR Spurwink Marsh the average was 0.85 (N=1).  In Massachusetts, Hg concentration at Plum Island Essex Co. Green Belt averaged 0.88 (range 0.62 - 1.17, N=14), at Parker River NWR Sub HQ Hg averaged 1.38 (range 1.18 - 1.62, N=7), at Parker River NWR Area A Hg averaged 1.65 (range 1.47 - 1.86, N=8), and at Parker River NWR Salt Pannes Hg concentrations averaged 1.94 (range 1.01 - 3.73, N=14) (Lane et al. 2008).  Mercury concentrations at Parker River Salt Pannes and Area A sites were significantly greater than at HQ and Essex Co. Green Belt on Plum Island, and Furbish Marsh.

d.

Data from 2007.
In Maine, Scarborough Marsh site concentrations averaged 0.53 (range 0.23 - 1.12, N=13), Rachel Carson NWR Furbish Across Road averaged 0.65 (range 0.56 - 0.78, N=9), Rachel Carson NWR Furbish Middle averaged 0.71 (0.54 - 0.99, N=14), and Rachel Carson NWR Furbish East blood Hg averaged 0.73 (range 0.53 - 1.02, N=22).  In New York, Wertheim NWR Hg averaged 0.83 (range 0.52 - 1.23, N=26).  In Rhode Island, Hg concentrations at John Chafee National Wildlife Research Center (NWRC) Middle Bridge site averaged 0.77 (range 0.62 - 1.04, N=6), John Chafee NWRC Stone Wall Marsh averaged 0.84 (range 0.51 - 1.23, N=12), and John Chafee NWRC at Pettaquamscutt Cove blood Hg averaged 0.95 (range 0.75 - 1.09, N=13).  In Massachusetts, Parker River NWR Area B concentrations averaged 1.15 (range 0.65 - 1.40, N=5), Parker River NWR Lot 2 blood Hg averaged 1.18 (range between 0.58 - 2.20, N=13), Parker River NWR Salt Pannes averaged 1.32 (range 0.52 - 2.20, N=36), and at William Forward WMA averaged 1.53 (range 1.39 - 1.77, N=3).  Saltmarsh sparrow blood Hg concentrations at Parker River in Massachusetts were significantly greater than refuges in Maine, Rhode Island, and New York (Lane et al. 2008).

2.

At all refuges, fledged (hatch year) sparrows were sampled and blood Hg concentrations ranged from 0.47 - 2.3 µg/g (ww) (Lane et al. 2008).

3.

Eggs were opportunistically collected from nests at various sites in New Hampshire and Maine (2004 - 2006) and were analyzed for Hg concentrations.  All eggs (N=39) had concentrations below 0.4 µg/g (ww) (Lane et al. 2008).

IV.

Petroleum

 

No exposure data available

Saltmarsh Sparrow Contaminant Response Data

I.

Organochlorine Contaminants

 

No response data available

II.

Cholinesterase-Inhibiting Pesticides

 

No response data available

III.

Trace Elements, Metals and Metalloids

1.

Sparrows at Parker River NWR had greater blood Hg concentrations compared to sparrows at the other marshes, and some individuals exceeded 1.18 µg/g ww, the level at which adverse effects are expected to occur in insectivorous birds (Lang et al. 2008).  In Maine at the Rachel Carson NWR in 2006, 16 nests were monitored for survival, and reproductive success appeared to be lower at the Parker River NWR where Hg blood concentrations were elevated, compared to sparrows at Rachel Carson NWR based on the 2006 season.  Therefore, elevated Hg concentrations may be adversely affecting nest success (Lang et al. 2008).

IV.

Petroleum

 

No response data available

References for Saltmarsh Sparrow

Birdlife International. 2010. Assessed June 16th 2010. (http://www.birdlife.org/)

Chesser, R.T., R.C. Banks, F.K. Barker, C. Cicero, J.L. Dunn, A.W. Kratter, I.J. Lovette, P.C. Rasmussen, J.V. Remsen, Jr., J.D. Rising, D.F. Stotz, and K. Winker. 2009. Fiftieth supplement to the American Ornithologists’ Union check-list of North American birds. The Auk. 126:705-714.

Deragon, W.R. 1988. Breeding ecology of seaside and sharp-tailed sparrows in Rhode Island salt marshes. Master's Thesis. University of Rhode Island, Kingston, RI, USA.

Erskine, A.J. 1992. Atlas of breeding birds of the Maritime Provinces. Nimbus Publishing and Nova Scotia Museum, Province of Nova Scotia and Nova Scotia Museum, Halifax, Nova Scotia. 274  pp.

Greenlaw, J.S. and J.D. Rising. 1994. Saltmarsh sharp-tailed sparrow (Ammodramus caudacutus) The Birds of North America Online. In A. Poole, ed., Cornell Lab of Ornithology, Ithaca. Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/112doi:10.2173/bna.112

Lane, O.P. and D.C. Evers. 2006. Methylmercury availability in New England
estuaries as indicated by saltmarsh sharp-tailed sparrow, 2004-2005. Report BRI 2006-01. BioDiversity Research Institute, Gorham, ME, USA.

Lane, O.P., A. Major, K. O’Brien, N. Pau and D.C. Evers. 2008. Methylmercury
availability in New England estuaries as indicated by saltmarsh sharp-tailed sparrow, 2004-2007. Report BRI 2008-11. BioDiversity Research Institute, Gorham, ME, USA.

Post, W. and J.S. Greenlaw. 1982. Comparative costs of promiscuity and monogamy: a test of reproductive effort theory.  Behav. Ecol. Sociobiol. 10:101-107.

Shriver, W.G., D.C. Evers, T.P. Hodgman, B.J. Macculloch, R.J. Taylor. 2006. Mercury in sharp-tailed sparrows breeding in coastal wetlands. Environ. Bioindi. 1:129-135.

U.S. Fish and Wildlife Service, Partners in Flight Program. National Conservation Status of Species Listing (http://www.partnersinflight.org/WatchListNeeds/). Accessed June 17th 2010.

Worth, C.B. 1972. Of Mosquitoes, Moths, and Mice. W. W. Norton & Co, NY, USA.

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