Winter flocks on coastal bays may number in the thousands. Photo: Dick Dickinson/Audubon Photography Awards, Breeding adult male. It also eats seeds and aquatic plants. 1993). National Audubon Society Diet / Feeding: They main diet consists of mollusks and aquatic plants. Data are provided as Table S1, Supplemental Material. Photo: Brian Kushner. Lesser Scaup look like they forgot to comb their hair, having a pointed rear crown. Amphipod populations have increased and native gastropods decreased in the presence … Although their diet varies with their habitat and the season, animal matter is the predominantly makes up their diet. Current mean individual prey mass of Amphipoda and Bivalvia in Minnesota were 86.6% and 85.1% lower than historical levels, respectively. Found at DOI: https://doi.org/10.3996/052019-JFWM-036.S2 (2.74 MB PDF). In winter often seen on lakes and bays in dense flocks, numbering hundreds or even thousands, and often with no other species of ducks associated with them. Help power unparalleled conservation work for birds across the Americas, Stay informed on important news about birds and their habitats, Receive reduced or free admission across our network of centers and sanctuaries, Access a free guide of more than 800 species of North American birds, Discover the impacts of climate change on birds and their habitats, Learn more about the birds you love through audio clips, stunning photography, and in-depth text. The lesser scaup is found on freshwater marshes, lakes, ponds, and bays during breeding season. It is possible that premigratory hyperphagia could be partially responsible for this result, because scaup seem to leave Lake Pontchartrain by February (C. Stroud, personal observation). For example, in southwest Louisiana, dwarf surf clams represented over 99% of the total number of food items consumed (Harmon 1962). We defined the selection index as: ŵi = ôi/p̂i, where ŵi was the selection index for food item i, ôi was the proportion of a food type in the diet, and p̂i was the proportion in which it was available on Lake Pontchartrain. Similar to lesser scaup, Chironomidae was the most commonly occurring prey item in greater scaup, which occurred in 88% of the diets, or composed 74% of their overall diet… Selection index values ranged from 0 to ∞; values > 1.0 indicated that scaup showed positive selection for a prey species and values < 1.0 indicated avoidance. Subject: Diet of Lesser Scaup Wintering on Lake Pontchartrain, Louisiana, (Optional message may have a maximum of 1000 characters.). Type in your search and hit Enter on desktop or hit Go on mobile device. Autumn diet of greater scaup, lesser scaup, and long‐tailed ducks on eastern Lake Ontario prior to zebra mussel invasion. However, since they are more abundant at higher salinities (Poirrier et al. A closer look reveals black-and-white males and chocolatey-brown females floating on the surface and diving below to eat aquatic invertebrates and plants. Main migration is rather late in fall and early in spring. 2012; Ross et al. The two species of scaup sometimes occur in the same places, but they tend to keep to themselves rather than mixing freely. Eighty-two percent of scaup consumed dark false mussels Mytilopsis leucophaeata and 57% consumed dwarf surf clams Mulinia lateralis; both foods were selected by scaup, but were uncommon in benthic samples. One of the most numerous and widespread diving ducks in North America, especially on inland waters. However, scaup diets in Louisiana have been shown to be highly variable among sites: scaup consumed primarily fish on Lake Borgne ( Rogers and Korshgen 1966 ), primarily seeds on Catahoula Lake ( Moore et al. Mollusks are a primary food source for wintering scaup throughout their range (Hoppe et al. It’s a challenging ID, but head shape can take you a long way. Males are slightly larger than females. Our goal was to determine important diet items for scaup wintering on Lake Pontchartrain, especially in relation to their availability in the benthic substrate. Includes mollusks, plant material. Diet shifts of lesser scaup are consistent with the spring condition hypothesis: Series title: Canadian Journal of Zoology: DOI: 10.1139/Z06-047: Volume: 84: Issue: 6: Year Published: 2006: Language: English: Contributing office(s) Northern Prairie Wildlife Research Center: Description: 8 p. Larger Work Type: Article: Larger Work Subtype : Journal Article: Larger Work Title: Canadian … A species new to the British fauna, Direct recovery rates of lesser scaup banded in northwest Minnesota: sources of heterogeneity, Temporal changes of populations and trophic relationships of wintering diving ducks in Chesapeake Bay, Rangia cuneata clam decline in Lake Pontchartrain from 2001 to 2014 due to an El Niño Southern Oscillation shift coupled with a period of high hurricane intensity and frequency, Acute disturbance of Lake Pontchartrain benthic communities by Hurricane Katrina, Lessons learned from a decade of assessment and restoration studies of benthic invertebrates and submersed aquatic vegetation in Lake Pontchartrain, Journal of Coastal Research Special Issue, Fall foods of lesser snow geese in the James Bay region, R: A language and environment for statistical computing, Food use and nutrition of black ducks nesting in Maine, Relative foraging value to Lesser Scaup ducks of native and exotic clams from San Francisco Bay, Foods of Lesser Scaups on breeding, migration, and wintering areas, Combined effects of climate, predation, and density dependence on Scaup population dynamics, Factors influencing the salinity regime of Lake Pontchartrain, Louisiana, a shallow coastal lagoon: analysis of a long-term data set, Bluebills and bayou bivalves: hurricane-driven trophic cascades affect wintering abundance of Lesser Scaup in Louisiana, Bias associated with food analysis in gizzards of blue-winged teal, Advantages in mathematically weighting waterfowl food habits data, Food habits of diving ducks in the Carolinas, Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies, U.S. Department of the Interior (see Supplemental Material, Reference S2), Body mass of Lesser Scaup during fall and winter in the Mississippi Flyway, This site uses cookies. Because of declines in foraging quality at spring migration areas in the upper Midwest, it may be increasingly important for scaup to depart major wintering areas with larger nutrient reserves (Austin et al. 1991). Their black heads have gloss that can vary from purple to green depending on the angle. Five species of mollusks (Figure 1) comprised 98% of the total number of food items and nearly 100% of the aggregate dry weight consumed. The sides and belly are white and the back is white with grey spots. Rangia and dark false mussels were the dominant prey species consumed by scaup on Lake Pontchartrain and accounted for large percentages of the total number of food items and dry weight consumed. The spring condition hypothesis (SCH) states that the current decline of the North American scaup population (Lesser [Aythya affinis] and Greater Scaup [A. marila] combined) is due to a decline in quality or availability of scaup foods on wintering, spring migration, or breeding areas that has caused a reduction in female body condition and subsequent reproductive success. Lake Pontchartrain is a 1,630 km2 oligohaline estuarine lagoon in southeastern Louisiana with an average salinity of 3.9 parts per thousand, an average depth of 3.7 m, and a maximum depth of 5 m (Sikora and Kjerfve 1985). Can be very active when feeding, diving and surfacing repeatedly. Dark false mussels were the most selected mollusk, followed by dwarf surf clams (Table 3, Figure 2). 1991). The diet of the lesser scaup is mainly composed of aquatic invertebrates such as insects, crustaceans, and mollusks. Some displays may be performed underwater. Forages by diving and swimming underwater; sometimes by dabbling or up-ending in shallow water. We used linear regression to determine whether the total number of food items consumed (dependent variable) varied by sex, age (independent factor variables), time of collection, or collection date (independent continuous variables). 2009), and the species likely represents a large component of annual scaup diets on the estuary. [2019] published results that link scaup abundance to the abundance of medium-sized rangia clams). By continuing to use our website, you are agreeing to, Submit to Journal of Fish and Wildlife Management, Journal of Fish and Wildlife Management: Online Early, Journal of Fish and Wildlife Management: Current and Available Issues, https://doi.org/10.3996/052019-JFWM-036.S1, https://doi.org/10.3996/052019-JFWM-036.S2, https://doi.org/10.3996/052019-JFWM-036.S3, https://doi.org/10.1111/j.1365-2486.2011.02541.x. These trends were driven largely by the last two sampling occasions; using collection date as a factor, we found that scaup food consumption increased by 24.8 items on the last collection date (P < 0.05). Our data also show that at least some Lesser Scaup remain on the lower Great Lakes throughout winter and may not … Each species account is written by leading ornithologists and provides … After drying we determined the dry mass of each species and size class to the nearest 0.1 mg. To sample the mollusks available to foraging scaup, we collected three replicate dredge samples near six randomly selected scaup collection sites using a 15-cm2 petite Ponar dredge (Abadie and Poirrier 2000; Brammer et al. in biology from Queen's University in 1970 and his M.Sc. 1999; Richman and Lovvorn 2004). White for assistance collecting scaup. Table S1. 1998), and primarily midge larvae (Chironomidae) on Rockefeller Wildlife Refuge (Afton and Ankney 1991). 1986; Custer and Custer 1996), and indeed are common in Lake Pontchartrain (Poirrier et al. Text © Kenn Kaufman, adapted from Thus, it is possible that dark false mussels provide scaup with an easily accessible food source at reliable locations, and indeed, several of our collection locations were near the Lake Pontchartrain Causeway. Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future. Seeds and other parts of plants are also eaten. The National Audubon Society protects birds and the places they need, today and tomorrow, throughout the Americas using science, advocacy, education, and on-the-ground conservation. Lesser Scaup Food. Aythya affinis Traditionally, lesser scaup (a.k.a. 2007; Poirrier et al. Migrates in flocks. The more northerly of our two scaup species, the Greater is also found across northern Europe and Asia. Behavior. In Minnesota, we found that the current aggregate percentage of Amphipoda (an important food item) in lesser scaup diets was 94% lower than … Strongly preferred foods cluster at the upper left of the diagram, above the 1:1 selection ratio line. But that's because they were describing two different birds. Males have black breast, medium gray back, white sides, and yellow eye. ; Bill: Both scaups have similar bills, but close observation will reveal … We excluded contents from the gizzard and intestines, because the gizzard imposes a sampling bias by retaining harder food items (Dirschl 1969; Swanson and Bartonek 1970). We used a dissecting microscope to sort esophageal and proventricular contents by species into 5-mm size classes based on length. Range. Avian Conservation and Ecology 1, Resources selection by animals: statistical design and analysis for field studies. Elements of courtship display by male include a shake of the head, followed by throwing the head far back and bringing it forward very quickly; exaggerated bowing movements; ritualized preening. 1998 ), and primarily midge larvae (Chironomidae) on Rockefeller Wildlife Refuge ( Afton and Ankney 1991 ). We evaluated the diet of 60 scaup collected from a major wintering site in Louisiana, Lake Pontchartrain. Our results confirmed that scaup wintering on Lake Pontchartrain fed almost exclusively on mollusks, in accordance with previous work conducted by Bowman (1973). Mean mass of scaup diet samples throughout the upper-Midwest were 77 mg (49%) and 87 mg (52%) lower than those of historical studies in Minnesota and Manitoba, respectively. Life Cycle. Lives of North American Birds. Immediately after collection, we injected scaup esophagi with 10% buffered formalin to prevent further digestion (Afton and Ankney 1991). 2019). See more ideas about waterfowl, duck, birds. They were collected using 12-gauge shotguns and #2 steel shot, under U.S. Sex, age, and collection time did not affect the number of prey items or total dry weight of prey consumed (all P > 0.05). Compared with other prey species, dark false mussels and dwarf surf clams were relatively rare in the benthic dredge samples, with both species accounting for < 4% of the total number of food items available (Table 3). 1999; Richman and Lovvorn 2004). Percent occurrence of food items, aggregate percent dry weight, and frequency of food item occurrence in lesser scaup Aythya affinis that were collected during the winter of 2016–2017 from Lake Pontchartrain, Louisiana. Found at DOI: https://doi.org/10.3996/052019-JFWM-036.S3 (3.96 MB PDF). Esophageal and proventricular contents were combined for analysis to maximize sample size (Afton et al. Two species of snails Texadina sphinctostoma and Probythinella protera were consumed in moderate numbers (Table 2), but accounted for < 2% of aggregate dry mass. Diet shifts of lesser scaup are consistent with the spring condition hypothesis Author ANTEAU, Michael J 1; AFTON, Alan D 2 [1] School of Renewable Natural Resources, Louisiana State University, Baton Rouge, LA 70803, United States [2] US Geological Survey (USGS), Louisiana Cooperative Fish and Wildlife Research Unit, Louisiana State University, Baton Rouge, LA … Journal of Fish and Wildlife Management 1 December 2019; 10 (2): 567–574. Diet shifts of lesser scaup are consistent with the spring condition hypothesis. Sometimes feeds at night. Afton and Anderson (2001) formalized these ideas, and they developed the spring condition hypothesis, which postulates that reproductive success has declined relative to historic levels because female scaup are arriving on breeding grounds in poorer body condition than in the past. Although rangia ≥ 11 mm to < 16 mm long accounted for only 8% of the total number of food items consumed, the size class represented 36% of the aggregate dry weight ingested. The continental breeding population of lesser scaup Aythya affinis (hereafter scaup) declined for 20 y between the mid-1980s and the mid-2000s, and despite recent increases, remains 13% below the long-term average of 5.02 ± 0.04 million (USFWS 2017). Legal Notices Privacy Policy Contact Us. Olive-buff. Summers around large marshes in prairie or forested regions. It has been reported that both the Lesser and the Greater Scaup have shifted their traditional migration routes to take advantage of the presence of zebra mussels in Lake Erie. Lesser scaup forage mainly by sifting through the bottom mud, usually after diving and swimming underwater, occasionally by dabbling without diving. Carney SM. 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