spoil islets in and near Merritt Island NWR on the east coast of Florida were 

 located 6-79 ft (2-24 m) from the water (mean = 27.8 ft, or 8.47 m) , but most 

 (78.9%, n = 114) were found 10-40 ft (3.1-12.2 ra) from water. Excluding cover 

 for nests under Australian pines ( Casuarina equisetif olia ) , which Steiglitz and 

 Wilson considered atypical, height of cover ranged from 0.5 to 8 ft (0.15-2.4 m) . 

 In favored nesting sites, however, the cover was typically 1.25-2 ft (0.38-0.61 m) 

 tall. Ducks in this study area preferred to nest in pure stands of seashore pas- 

 palum ( Paspalum vaginatum ); broomsedge ( Andropogon sp.) was also commonly used. 

 A few nests were also found among or under wax myrtle shrubs ( Cerothamnus ceri - 

 f erus ) , red mangrove ( Rhizophora mangle ) , scrub palmetto ( Sabal etonia ) , or Aus- 

 tralian pine. 



Birds nesting along the Texas coast preferred to nest on slight ridges in 

 heavy stands of saltmeadow cordgrass ( Spartina patens ) ♦ In inland areas, pre- 

 ferred sites were in tall cover in abandoned fields, on road sides, and on 

 levees (Singleton 1953). 



Feeding and Offshore Mottled Ducks feed in or near the areas in which 

 they nest. We know of no records of their occurring offshore. 



FOOD AND FEEDING BEHAVIOR 



The Mottled Duck has a relatively varied diet for a dabbling duck and eats 

 more animal foods than do most of the ducks in the genus Anas . A few studies 

 have reported in some detail the foods consumed. We have summarized these for 

 Florida and Texas below. According to Palmer (1976a), much the same foods are 

 eaten along the Louisiana coast and his work should be consulted for a list of 

 these, as well as for other foods not mentioned here. 



Florida Beckwith and Hosford (1956, 1957) reported the contents of 144 

 gizzards collected from October 1953 through November 1954 in the vicinity of 

 Lake Okeechobee in Glades County. On the basis of identified material only, 

 these birds consumed an average of 87.2% plant material and 12.8% animal matter. 

 Foods utilized varied from season to season, with the diet composed of as much 

 as 100% plant food (fall, 1953 and 1954; winter 1953-54) or as little as 61% 

 (summer, 1954). Seventy-seven species of plants of 51 genera were consumed. 

 Fall plant foods making up more than 3% (by volume) of the diet in any given 

 year were ragweed ( Ambrosia elatior - 30.7%), dotted smartweed ( Polygonum punc - 

 tatum - 28.3%), a Panicum ( agrostoides ? - 17.4%), a Paspalum ( cilatifolium ? - 

 12.4%), and ovateleaved marsh- pennywort ( Centella asiatica - 3.6%). Major foods 

 during one or the other winters were gulfcoast spikerush ( Eleocharis cellulosa - 

 14.6%), the marsh-pennywort (12.2%), Carolina fanwort ( Cabomba carol -tnjana - 

 11.8%), ragweed (8.6%), guava ( Psidium guajava - 6.4%), dotted smartweed (3.8 

 to 4.1%), and a beakrush ( Rhynchospora sp. - 3.4%). The principal plant foods 

 taken during the spring of 1954 were dotted smartweed (23.4%) and Puerto Rico 

 smartweed ( Persicaria portoricensis - 10.4%), while the major plant foods eaten 

 that summer were Bartow panicgrass ( Panicum bartowense - 23.8%), dotted smart- 

 weed (5.1%), and mudbank paspalum ( Paspalum dissectum - 4.5%). Animal foods 

 eaten were not as adequately identified by Beckwith and Hosford, but consisted 

 largely of insects, particularly aquatic beetles, and snails. 



In a subsequent study, Stieglitz (1972) compared food habits at inland 



205 



