Nestling foods of the savannah sparrow

1984 ◽  
Vol 62 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Marie Meunier ◽  
Jean Bédard
Keyword(s):  
Breeding Season ◽  
Temporal Changes ◽  
Prey Abundance ◽  
Large Prey ◽  
Passerculus Sandwichensis ◽  
Main Prey ◽  
Savannah Sparrow ◽  
Close Relationship ◽  
Males And Females ◽  
Prey Items

The diet of savannah sparrow (Passerculus sandwichensis) nestlings was monitored at Îsle Verte, Québec, during the 1980 breeding season. Adults carried exclusively arthropods to the nest. The main prey types found were Lepidoptera and Hymenoptera larvae, larval and adult Diptera and Homoptera. The proportion of different prey types in the diet varied during the season but there was no close relationship between temporal changes in the indices of prey abundance in the habitat and the type of prey chosen by the adult birds. Both the type and size of prey brought to the nest changed with the age and number of nestlings (aged 4–10 days). The proportion of Homoptera in the diet decreased sharply with age while that of Lepidoptera and Diptera increased. Adults feeding broods of four brought a larger proportion of large prey items (Lepidoptera and Hymenoptera larvae) than those feeding broods of a lesser size; to these they brought a larger proportion of smaller items such as Diptera and adult Lepidoptera. Males and females brought the same major prey types to the nest but not in the same proportions.

Parental care in the savannah sparrow

1983 ◽  
Vol 61 (12) ◽  
pp. 2836-2843 ◽  
Author(s):  
Jean Bédard ◽  
Marie Meunier
Keyword(s):  
Parental Care ◽  
Dry Weight ◽  
Food Delivery ◽  
Male And Female ◽  
Passerculus Sandwichensis ◽  
Short Period ◽  
Savannah Sparrow ◽  
Gross Energy ◽  
Males And Females ◽  
Prey Items

The apportioning of parental care by male and female during the nestling stage was studied in the savannah sparrow (Passerculus sandwichensis). Brooding by both parents amounted to 66% of the daylight period during the first 2 days after hatching and decreased to 12% toward the end of the nestling stage. Broods of two received more brooding care than broods of either three or four nestlings during the last 2 days of rearing. We monitored the identity, size, and number of all the prey items (exclusively arthropods) brought by 32 nesting pairs during 628 h of observation. These estimates were later converted to estimates of dry weight of food transported (in milligrams per nestling per hour) by using weight measurements of standard prey items. The number of food deliveries increased steadily with nestling age. Males and females contributed nearly equally in this respect, with some exceptions. Estimates of gross energy carried to the nestlings peaked markedly on days 5 and 6 and decreased afterwards. During this short period, the male contributed significantly more than the female in terms of gross food energy transported. We conclude that the birds can tune their feeding contribution to the nest in subtle ways that the monitoring of food delivery rates alone cannot adequately describe.

Breeding Biology of the Savannah Sparrow on Kent Island

The Auk ◽  
1978 ◽  
Vol 95 (2) ◽  
pp. 235-246 ◽  
Author(s):  
Clara L. Dixon
Keyword(s):  
New Brunswick ◽  
Clutch Size ◽  
Breeding Season ◽  
Breeding Population ◽  
Nesting Success ◽  
Breeding Biology ◽  
Passerculus Sandwichensis ◽  
Herring Gulls ◽  
Savannah Sparrow ◽  
The Mean

Abstract I studied the breeding biology of the Savannah Sparrow (Passerculus sandwichensis) on Kent Island, New Brunswick, Canada from 1964 through 1968. I estimated the breeding population to be 125-135 pairs $(412-445\ \text{individuals}/{\rm km}^{2})$. The mean number of nests produced per female, including those destroyed by predators, was 2.97. Clutch size ranged from 2 to 5. The mean clutch size based on 1,142 eggs in 284 nests of known clutch size was 4.02. Not only was the four-egg clutch most numerous but a greater percentage of eggs in the four-egg clutches hatched and the mean number of young fledged per nest was also highest. The mean incubation period was 12.2 days, the mean duration of nestling life was 9 days, and the approximate length of the breeding season as 52 days. The daily mortality rate of eggs was 11.9% and of nestlings 2.1%. Predation was the major factor affecting reproductive success; 50.5% of all nests located were destroyed by predators. The main nest predators were Common Crows and Herring Gulls. Of the nests destroyed by predators, 87.8% contained eggs rather than nestlings. The intense predation necessitated high nest replacement. The mean interval between the termination of one nest and the appearance of the first egg in the succeeding nest was 6.3 days. If successive nests are destroyed on the day incubation begins, it is hypothetically possible for a pair to produce four nests during a single breeding season; many birds in the population produce at least three. Although enough time was available for birds to fledge two broods in a season, few of them fledged more than one. Thus, the nesting success was low (success from egg to hatching 18.1%). High nest replacement compensated for high egg mortality, and an average of 2.16 young per pair were fledged per season.

scholarly journals Intraspecific variation in the diet of the Mexican garter snakeThamnophis eques

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4036 ◽  
Author(s):  
Javier Manjarrez ◽  
Martha Pacheco-Tinoco ◽  
Crystian S. Venegas-Barrera
Keyword(s):  
Intraspecific Variation ◽  
Resource Competition ◽  
Prey Availability ◽  
General Pattern ◽  
Stomach Contents ◽  
Large Prey ◽  
Male And Female ◽  
Males And Females ◽  
Prey Items

The Mexican Garter Snake (Thamnophis eques)is a terrestrial-aquatic generalist that feeds on both aquatic and terrestrial prey. We describe size-related variation and sexual variation in the diet ofT. equesthrough analysis of 262 samples of identifiable stomach contents in snakes from 23 locations on the Mexican Plateau. The snakeT. equeswe studied consumed mostly fish, followed in lesser amounts by leeches, earthworms, frogs, and tadpoles. Correspondence analysis suggested that the frequency of consumption of various prey items differed between the categories of age but not between sex of snakes, and the general pattern was a reduction of prey item diversity with size of snake. Snake length was correlated positively with mass of ingested prey. Large snakes consumed large prey and continued to consume smaller prey. In general, no differences were found between the prey taxa of male and female snakes, although males ate two times more tadpoles than females. Males and females did not differ in the mass of leeches, earthworms, fishes, frogs and tadpoles that they ate, and males and females that ate each prey taxon were similar in length. We discuss proximate and functional determinants of diet and suggest that the observed intraspecific variation inT. equescould be explored by temporal variation in prey availability, proportions of snake size classes and possible sexual dimorphism in head traits and prey dimensions to assess the role of intersexual resource competition.

The Effect of Egg Temperature on Attentiveness in the Belding's Savannah Sparrow

The Auk ◽  
1984 ◽  
Vol 101 (3) ◽  
pp. 556-566 ◽  
Author(s):  
Stephen D. Davis ◽  
Joseph B. Williams ◽  
Wendy J. Adams ◽  
Stephanie L. Brown
Keyword(s):  
Breeding Season ◽  
Air Temperature ◽  
Direct Response ◽  
Passerculus Sandwichensis ◽  
Savannah Sparrow ◽  
Diurnal Fluctuations ◽  
Lower Limits

Abstract We manipulated egg temperatures in nests of the Belding's Savannah Sparrow, (Passerculus sandwichensis beldingi), an open-nesting passerine of which only the female incubates. Females increased their attentiveness by 22.0% when we cooled their eggs and decreased their attentiveness by 28.4% when we warmed their eggs. The range of adjustment approximated the upper and lower limits of attentiveness observed for our population during one breeding season; adjustments were primarily made by changing the length of both attentive and inattentive periods. Our results indicate that these birds adjust their attentive time in direct response to fluctuations in egg temperature, independently of diurnal fluctuations in air temperature. They also support the hypothesis that attentiveness is ultimately controlled by an internal rhythm and is only modified by, but not completely explained by, responses to egg temperature.

scholarly journals Intraspecific variation in the diet of the Mexican garter snake Thamnophis eques

2016 ◽  
Author(s):  
Javier Manjarrez ◽  
Martha Pacheco-Tinoco ◽  
Crystian S Venegas-Barrera
Keyword(s):  
Intraspecific Variation ◽  
Resource Competition ◽  
Prey Availability ◽  
General Pattern ◽  
Stomach Contents ◽  
Garter Snake ◽  
Large Prey ◽  
Garter Snakes ◽  
Males And Females ◽  
Prey Items

The Mexican Garter Snake (Thamnophis eques) is a terrestrial-aquatic generalist because it feeds on both aquatic and terrestrial prey. We describe size-related variation and slight sexual variation in the diet of Thamnophis eques through analysis of 262 samples of identifiable stomach contents in snakes from 23 locations on the Mexican Plateau. The Mexican Garter Snakes we studied ate prey items mostly fish, followed in lesser amounts, respectively, by leeches, earthworms, frogs, and tadpoles. Correspondence analysis suggested that the frequency of consumption of various prey items differed between the categories of age and sex of snakes, and the general pattern was a reduction of prey item diversity with size of snake. Snake length was correlated positively with mass of ingested prey. Large snakes consumed large prey and continued to consume smaller prey. In general, no differences were found between the prey taxa of male and female snakes, although males ate two times more tadpoles than females. Males and females did not differ in the mass of leeches, earthworms, fishes, frogs and tadpoles that they ate, and males and females that ate each prey taxon were similar in length. We discuss proximate and functional determinants of diet and suggest that the observed intraspecific variation in Mexican Garter Snakes could be explored by temporal variation in prey availability, proportions of snake size classes and possible sexual dimorphism in head traits and prey dimensions to assess the role of intersexual resource competition.

scholarly journals Intraspecific variation in the diet of the Mexican garter snake Thamnophis eques

2016 ◽  
Author(s):  
Javier Manjarrez ◽  
Martha Pacheco-Tinoco ◽  
Crystian S Venegas-Barrera
Keyword(s):  
Intraspecific Variation ◽  
Resource Competition ◽  
Prey Availability ◽  
General Pattern ◽  
Stomach Contents ◽  
Garter Snake ◽  
Large Prey ◽  
Garter Snakes ◽  
Males And Females ◽  
Prey Items

The Mexican Garter Snake (Thamnophis eques) is a terrestrial-aquatic generalist because it feeds on both aquatic and terrestrial prey. We describe size-related variation and slight sexual variation in the diet of Thamnophis eques through analysis of 262 samples of identifiable stomach contents in snakes from 23 locations on the Mexican Plateau. The Mexican Garter Snakes we studied ate prey items mostly fish, followed in lesser amounts, respectively, by leeches, earthworms, frogs, and tadpoles. Correspondence analysis suggested that the frequency of consumption of various prey items differed between the categories of age and sex of snakes, and the general pattern was a reduction of prey item diversity with size of snake. Snake length was correlated positively with mass of ingested prey. Large snakes consumed large prey and continued to consume smaller prey. In general, no differences were found between the prey taxa of male and female snakes, although males ate two times more tadpoles than females. Males and females did not differ in the mass of leeches, earthworms, fishes, frogs and tadpoles that they ate, and males and females that ate each prey taxon were similar in length. We discuss proximate and functional determinants of diet and suggest that the observed intraspecific variation in Mexican Garter Snakes could be explored by temporal variation in prey availability, proportions of snake size classes and possible sexual dimorphism in head traits and prey dimensions to assess the role of intersexual resource competition.

Observation on the breeding biology of Polypedates teraiensis (Dubois, 1987) (Amphibia: Rhacophoridae)

2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.
Keyword(s):  
Sexual Dimorphism ◽  
Breeding Season ◽  
Sound Production ◽  
Reproductive Function ◽  
Breeding Biology ◽  
Tree Frog ◽  
University Campus ◽  
Morphometric Measurements ◽  
Advertisement Calls ◽  
Males And Females

The breeding biology of tree frog, Polypedates teraiensis was studied during the breeding season at Mizoram University Campus. It was found that sound production by male during the breeding season was primarily a reproductive function and advertisement calls attract females to the breeding areas and announce other males that a given territory is occupied. The aim of this study was to provide the detailed information on the breeding behaviour and the advertisement calls of Polypedates teraiensis. The morphometric measurements of the amplecting pairs (males and females) for sexual dimorphism along with clutch sizes were also studied.

scholarly journals Sources of variation in the feeding ecology of the piked spurdog (Squalus megalops): implications for inferring predator–prey interactions from overall dietary composition

2005 ◽  
Vol 62 (6) ◽  
pp. 1076-1094 ◽  
Author(s):  
J. Matías Braccini ◽  
Bronwyn M. Gillanders ◽  
Terence I. Walker
Keyword(s):  
Spatial And Temporal Variation ◽  
Dietary Composition ◽  
Bootstrap Analysis ◽  
Predator Prey ◽  
Ecological Relationships ◽  
Wide Range ◽  
Opportunistic Predator ◽  
Sources Of Variation ◽  
Males And Females ◽  
Prey Items

Abstract Sources of variation in dietary composition were examined in the piked spurdog (Squalus megalops). The species is an opportunistic predator that consumes a wide range of prey items. When importance of prey was measured by weight or occurrence, S. megalops preyed largely on molluscs and teleosts. However, when number of prey was considered, the main items were crustaceans. A bootstrap analysis showed that considerable variability can be expected in the importance of prey items in the species' overall diet. Regional, seasonal, and ontogenetic differences in dietary composition were found, but there were no differences between mature and immature sharks or between males and females. The spatial and temporal variation in diet exhibited by S. megalops and the intrinsic natural variability of the dietary composition of this opportunistic predator suggest that studies that infer predator–prey interactions from overall diet are likely to miss information on the ecological relationships among species and thus account for only part of these interactions.

Further data on Iranian marine nematode diversity, with description of three new Desmodoridae Filipjev, 1922 (Nematoda: Desmodorida) species from the Persian Gulf

Nematology ◽  
2021 ◽  
pp. 1-22
Author(s):  
Azadeh Gharahkhani ◽  
Ebrahim Pourjam ◽  
Daniel Leduc ◽  
Majid Pedram
Keyword(s):  
Persian Gulf ◽  
Buccal Cavity ◽  
First Record ◽  
The Body ◽  
Pharyngeal Bulb ◽  
Close Relationship ◽  
Nematode Diversity ◽  
Males And Females ◽  
The Persian Gulf ◽  
Amphidial Fovea

Summary The Desmodoridae is a diverse and widespread family of free-living nematodes. Here, we provide the first record of the group in the Persian Gulf and describe three new species: Metachromadoroides sinuspersici sp. n., Zalonema iranicum sp. n. and Z. supplementorum sp. n. Metachromadoroides sinuspersici sp. n. is characterised by finely annulated cuticle, short and stout cephalic sensilla, amphidial fovea on cuticular thickening, pharyngeal bulb well developed and partitioned into three sections, absence of precloacal supplements, and presence of 6-8 pairs of rounded postcloacal papillae. Zalonema iranicum sp. n. is characterised by papilliform subcephalic sensilla (best observed with SEM), convex cephalic capsule, large multispiral amphidial fovea with 4-5 turns in both males and females, buccal cavity with one ventrosublateral and two dorsal teeth and posterior body of males with lateral alae extending from the last third of the body to the cloacal aperture and ventral alae extending 1395-2250 μm anterior to the cloacal aperture, and no precloacal supplements. Zalonema supplementorum sp. n. is characterised by four subcephalic sensilla 1-2 μm long, multispiral amphidial fovea with three turns in both males and females, buccal cavity with one dorsal and two ventrosublateral teeth, males with lateral alae present on each side of body from posterior half of body to cloacal aperture, ventral alae extending 942-1257 μm anterior to cloacal aperture, strongly cuticularised spicules 41-43 μm long, and 12-16 precloacal supplements. Near full length SSU and partial D2-D3 LSU sequences are provided for M. sinuspersici sp. n. and Z. iranicum sp. n., and the COI sequence is provided for Z. iranicum. The SSU phylogeny suggests a close relationship between M. sinuspersici sp. n. and Metachromadora and Metachromadoroides species and the monophyly of Zalonema (after currently available data). The LSU phylogeny suggests an affinity between Metachromadoroides and Zalonema with Spirinia and Acanthopharynx, respectively.

2. Mating systems, or who goes with whom, and for how long

2018 ◽  
pp. 16-33
Author(s):  
Leigh W. Simmons
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Social Relationships ◽  
Breeding Season ◽  
Mating Systems ◽  
Practical Applications ◽  
Multiple Partners ◽  
Monogamous Species ◽  
Genetic Techniques ◽  
Males And Females

‘Mating systems, or who goes with whom, and for how long’ examines the variation in how males and females associate during the breeding season, ranging from brief couplings with multiple partners to lifelong monogamy. It also shows how the discovery that females mate with many partners, even in supposedly monogamous species such as songbirds, was made possible by modern genetic techniques. Variation in mating systems holds considerable implications for the operation of sexual selection. The way that animal mating systems have been explained historically is outlined before considering how a more contemporary understanding of genetic and social relationships has reshaped our thinking and how understanding a species’ mating system can have practical applications.

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