scholarly journals A flyway perspective of foraging activity in Eurasian Green-winged Teal, Anas crecca crecca

2007 ◽  
Vol 85 (1) ◽  
pp. 81-91 ◽  
Author(s):  
C. Arzel ◽  
J. Elmberg ◽  
M. Guillemain

Time–activity budgets in the family Anatidae are available for the wintering and breeding periods. We present the first flyway-level study of foraging time in a long-distance migrant, the Eurasian Green-winged Teal, Anas crecca crecca L., 1758 (“Teal”). Behavioral data from early and late spring staging, breeding, and molting sites were collected with standardized protocols to explore differences between the sexes, seasons, and diel patterns. Teal foraging activity was compared with that of the Mallard, Anas platyrhynchos L., 1758 and Northern Shoveler, Anas clypeata L., 1758, and the potential effects of duck density and predator-caused disturbance were explored. In early spring, foraging time was moderate (50.5%) and mostly nocturnal (45%). It increased dramatically in all three species at migration stopovers and during molt, mostly because of increased diurnal foraging, while nocturnal foraging remained fairly constant along the flyway. These patterns adhere to the “income breeding” strategy expected for this species. No differences between the sexes were recorded in either species studied. Teal foraging time was positively correlated with density of Teal and all ducks present, but negatively correlated with predator disturbance. Our study suggests that Teal, in addition to being income breeders, may also be considered as income migrants; they find the energy necessary to migrate at staging sites along the flyway.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jade Carver ◽  
Morgan Meidell ◽  
Zachary J. Cannizzo ◽  
Blaine D. Griffen

AbstractTwo common strategies organisms use to finance reproduction are capital breeding (using energy stored prior to reproduction) and income breeding (using energy gathered during the reproductive period). Understanding which of these two strategies a species uses can help in predicting its population dynamics and how it will respond to environmental change. Brachyuran crabs have historically been considered capital breeders as a group, but recent evidence has challenged this assumption. Here, we focus on the mangrove tree crab, Aratus pisonii, and examine its breeding strategy on the Atlantic Florida coast. We collected crabs during and after their breeding season (March–October) and dissected them to discern how energy was stored and utilized for reproduction. We found patterns of reproduction and energy storage that are consistent with both the use of stored energy (capital) and energy acquired (income) during the breeding season. We also found that energy acquisition and storage patterns that supported reproduction were influenced by unequal tidal patterns associated with the syzygy tide inequality cycle. Contrary to previous assumptions for crabs, we suggest that species of crab that produce multiple clutches of eggs during long breeding seasons (many tropical and subtropical species) may commonly use income breeding strategies.


2014 ◽  
Vol 6 (1) ◽  
pp. 247-254
Author(s):  
Elizabeth A. St. James ◽  
Michael L. Schummer ◽  
Richard M. Kaminski ◽  
Edward J. Penny ◽  
L. Wesley Burger

Abstract Waterfowl hunting is important culturally and economically in North America. Few studies have evaluated the relationship between weekly hunting frequency and rate of ducks harvested. We evaluated the effect of hunting 2 or 4 d/wk on rate of ducks harvested on three Mississippi Wildlife Management Areas, USA, during three waterfowl hunting seasons, December–January 2008–2011. Harvest of all ducks combined, mallard Anas platyrhynchos, northern shoveler Anas clypeata, or green-winged teal Anas crecca per hunter day did not differ between areas hunted 2 or 4 d/wk, but increased with hours spent afield. We suggest Wildlife Management Areas may be hunted 4 d/wk without reducing duck harvest per hunter day. We recommend continued evaluations of weekly hunting frequency on rate of ducks harvested to sustain science-guided management of waterfowl hunting on Mississippi public lands and elsewhere.


Crustaceana ◽  
2014 ◽  
Vol 87 (14) ◽  
pp. 1648-1656 ◽  
Author(s):  
Yiwen Zeng ◽  
Colin McLay ◽  
Darren C. J. Yeo

A recent study by Griffen et al. (2012) drew a link between invasiveness and breeding strategy (income or capital breeding), a hitherto unconsidered life-history trait, in crabs. The methods used by the authors identified Carcinus maenas (Linnaeus, 1758) as a capital breeder and Hemigrapsus sanguineus (De Haan, 1853) as an income breeder. We extend this association of breeding strategies and invasiveness to other crab species and note that crabs in general are capital breeders based on the concurrent opposing trends of gonadosomatic index and hepatosomatic index during secondary vitellogenesis (indicating an endogenous source of nutrients for reproduction). We identify possible reasons why H. sanguineus may be regarded as an exception to this brachyuran life history pattern. Given that some species could be capable of a mixed breeding strategy, we propose experimental methods for determining such strategies.


1989 ◽  
Vol 67 (8) ◽  
pp. 2008-2012 ◽  
Author(s):  
Joseph M. Culp

Diel periodicity in foraging activity of the longnose dace (Rhinichthys cataractae) was determined by measuring dace activity over the stream bed, gut fullness, and the digestive state of prey items. Although most species of minnows are either diurnally or crepuscularly active, dace began foraging within 1 h after sunset with light levels near 10 lx and ceased before sunrise throughout the ice-free period. During the day few prey were taken as the dace remained under the shelter of stones. This nocturnal foraging pattern did not appear to be affected by spawning or seasonal changes in prey composition. Nocturnal foraging in dace is not likely a response to prey availability, but may be a response to avoid diel periods when salmonid competitors or visual predators are active.


2009 ◽  
Vol 83 (2) ◽  
pp. 181-189 ◽  
Author(s):  
D. Jouet ◽  
H. Ferté ◽  
C. Hologne ◽  
M.L. Kaltenbach ◽  
J. Depaquit

AbstractThe prevalence of human cercarial dermatitis (HCD) caused by bird schistosomes appears to be increasing in France, in light of the impact of tourism combined with high densities of wild aquatic hosts in freshwater areas. The present work expands our knowledge of schistosome systematics by including samples of bird schistosomes collected from their natural hosts in France. Heads (318) and viscera (81) of aquatic birds belonging to 16 species from five orders, collecting during the hunting seasons or found dead, were autopsied for nasal and visceral schistosomes. Eggs and/or adults were analysed by molecular methods using the D2 domain and the second internal transcribed spacer (ITS-2) region of rDNA to determine species. Even if nasal eggs were polymorphic according to the host, all haplotypes were similar to that of Trichobilharzia regenti. Marked diversity of visceral species was observed. Final hosts under natural conditions were reported. For the first time, Trichobilharzia franki is reported in its natural bird hosts, Anas platyrhynchos, Anas crecca, Aythya fuligula and Cygnus olor. We also identified T. szidati in A. crecca and Anas clypeata. Bilharziella polonica was found in six species of aquatic birds, including Grus grus. This finding is the first record of bird schistosomes in this aquatic bird. Three new taxa of visceral schistosomes in Anser anser are strongly suspected according to their haplotypes. Futhermore, a new haplotype of visceral schistosomes isolated in Cygnus olor and similar to Allobilharzia visceralis was identified.


2018 ◽  
Vol 96 (2) ◽  
pp. 97-106
Author(s):  
M.J. Rehberg ◽  
L.D. Rea ◽  
C.A. Eischens

We measured individual growth, looked for evidence of weaning, and examined the interaction of these changes with diving behavior in young-of-year Steller sea lion (Eumetopias jubatus (Schreber, 1776)) pups in Alaska, USA, during their first winter. Steller sea lions employ an income breeding strategy, in which females provision their young over an individually variable period of months to years. Thus, we set out to identify whether these young sea lions showed evidence of weaning during the challenging winter months, describe the nature of their growth during this time, and examine their behaviors in light of these changes. Between 2005 and 2008, we captured 71 pups during early winter and recaptured 33 of these pups in early spring. Mark–resight and stable nitrogen isotope ratios in vibrissae indicated most pups remained nutritionally dependent on adult females throughout the winter. All pups increased both mass and lipid mass, with half of growth contributed by lipid mass. Changes in behavior were not correlated with growth excepting a weak but significant effect on rate of vertical travel. This study demonstrated that capture–recapture of Steller sea lion pups is possible, provided seasonal timing, locations, and age classes are carefully considered for their likelihood of capture success.


1979 ◽  
Vol 57 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Robert A. MacArthur

Radiotelemetry techniques were employed to study the relationship between activity and abdominal temperature (Tb) changes in free-ranging muskrats (Ondatra zibethicus). Body cooling accompanied foraging activity by adults in winter and juveniles in summer and was retarded by periodic withdrawal from water. Net Tb decline during winter foraging rarely exceeded 2 °C and was relatively independent of foraging time for excursions exceeding 40 min duration. In addition to periodic rewarming within feeding shelters, muskrats appeared to avoid hypothermia during under-ice excursions by elevating Tb prior to entering water. This elevation was maximal (mean increase = 1.2 °C) for excursions exceeding 40 min duration. Comparable increases were not observed in summer.


2016 ◽  
Vol 94 (8) ◽  
pp. 575-581 ◽  
Author(s):  
A.J. Raquel ◽  
J.H. Devries ◽  
D.W. Howerter ◽  
R.T. Alisauskas ◽  
S.W. Leach ◽  
...  

Timing of breeding varies among waterfowl species and individuals, with strong effects on reproductive success, and may be related to habitat quality. Here, we analyse the start, span, and end of the nesting season for nine upland-nesting duck species at 166 Canadian Prairie–Parkland sites over 34 years to better characterize nesting patterns and test whether and how species respond to May pond abundances. Nesting metrics were compared between single-site versus multiple-site studies over 7 years to evaluate the effects of spatial scale and methodology. Strong, consistent differences in start of nesting were found among duck species, being earliest for Northern Pintail (Anas acuta L., 1758) and Mallard (Anas platyrhynchos L., 1758), followed by Northern Shoveler (Anas clypeata L., 1758), American Green-winged Teal (Anas crecca carolinensis Gmelin, 1789 = Anas carolinensis Gmelin, 1789), Blue-winged Teal (Anas discors L., 1766), American Wigeon (Anas americana Gmelin, 1789), Gadwall (Anas strepera L., 1758), and lastly by Lesser Scaup (Aythya affinis (Eyton, 1838)) and White-winged Scoter (Melanitta fusca deglandi (Bonaparte, 1850)). Span and end of nesting were related to May pond abundances, but the strength of these relationships varied among species, presumably reflecting the flexible (re-)nesting potential of individuals of some species in response to wetland-habitat quality.


2010 ◽  
Vol 2 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Rohtash Chand Gupta ◽  
Tirshem Kumar Kaushik ◽  
Surjit Kumar

Kaithal District is comprised of 2317 Km² Sq. Km area having six blocks Viz.:Kaithal, Kalayat, Pundri, Rajound, Ghula and Siwan located at a distance of 150 Kms from New Delhi toward North West. Its geographical position lies between 29° 48' 0 N latitude and between 76° 22' 60 E longitude.The present studies were carried between 2005-2008 with the help of Zenith Camera and telelens. In all, 63 species of Wetland birds belonging to 10 Orders, 38 genera and 16 families were observed in various village ponds in Kaithal District. Out of 63 species of wetland birds, 31 are winter migratory, 9 local migratory, 3 summers migratory and 20 species are resident birds. Considering IUCN categories, Black Ibis (Pseudibis papillosa) which belongs to Biome Restricted Species (BRS) was observed in three blocks viz. Kaithal, Pundri and Rajound of Kaithal district. In addition, Spotted Greenshank (Tringa guttifer) which has been placed in endangered category of IUCN was observed as single individual. But Black Ibis (Pseudibis papillosa) was observed in a group of three to seven. Northern Shoveller (Anas clypeata), which is reportedly coming from Central Russia and Caspian Siberia has been observed in very large groups of 200-250 and virtually spotted in each and every pond in Northern Haryana. Similarly, Northern Pintail (Anas acuta), Common Teal (Anas crecca), Common Pochard (Aythya ferina), Spot-billed Duck (Anas poecilorhyncha), Lesser-whistling Teal (Dendrocygna javanica) were also seen in relatively large groups. Common Pochard (Aythya ferina) is always observed in pure groups floating in the centre of relatively big ponds. In contrast, Gadwall (Anas strepera), Northern Shoveller (Anas clypeata), Northern Pintail (Anas acuta) and Common Teal (Anas crecca), share close proximity with each other in water and are found in mixed groups. Northern Shoveller (Anas clypeata), Bar- headed Goose (Anser indicus) and Northern Pintail (Anas acuta) stay between Octobers to April. Mallard (Anas platyrhynchos) stays in winter for shortest period between December and January. Maximum wetland birds observed in Kaithal District belong to Order Charadriiformes and to family Anatidae of Order Anseriformes. Spotted Greenshank (Tringa guttifer) is the peculiar to Pundri block only, in Kaithal District.


Author(s):  
Agustina Marciano ◽  
Laura Susana López-Greco ◽  
Karine Delevati Colpo

Reproduction is a costly process that depends on the management of available resources. Here, we aimed to understand the energetic strategies of females of the fiddler crab Leptuca uruguayensis (Nobili 1901), in a population with short reproductive seasons. For this, we developed an integrated approach to recognize the brooding time, spawning pattern modulated by female size, number of spawns per female, and content of reserves in the ovary and hepatopancreas. Based on the condition of the ovary and hepatopancreas, the reproductive season was divided into three periods. In each of these periods, it was possible to record a spawning event, which was mainly represented by large females. Most of the females had one spawn during the breeding season, and only large females had two spawns, with an interval of approximately two months. We propose that L. uruguayensis presents a mixed capital-income breeding strategy associated with the female size and period of the reproductive season. We conclude that large females make the greatest reproductive effort for the population, because they can have two spawns, whereas medium and small females make a low contribution because they are still investing energy in somatic growth to increase fecundity in the next reproductive season.


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