Age- and sex-related morphological and physiological differences influence escape capacity in House Sparrows (Passer domesticus)

2010 ◽  
Vol 88 (10) ◽  
pp. 1021-1031 ◽  
Author(s):  
L. De Neve ◽  
J. D. Ibañez-Alamo ◽  
M. Soler
Keyword(s):  
Escape Response ◽  
Passer Domesticus ◽  
First Year ◽  
Cell Mediated Immunity ◽  
Animal Performance ◽  
House Sparrows ◽  
Factors Affecting ◽  
Age Related ◽  
Animal Populations ◽  
Age And Sex

Sexual dimorphism and age-related differences are sources that contribute to morphologic and physiologic variation within animal populations. Measurement of animal performance may indicate whether this variation is functionally relevant. Our study aimed to experimentally test this statement in a captive population of House Sparrows ( Passer domesticus (L., 1758)) by examining age- and sex-related differences in escape response and its relationship to several morphological (tarsus, wing, tail lengths, and body mass) and physiological traits (cell-mediated immunity, natural antibodies, complement activity, hematocrit, and stress response). Escape response from a predator is considered a good variable to measure animal performance, because natural selection clearly favours individuals that avoid predators successfully. Our experimental design also aimed to standardize possible confounding factors affecting escape behaviour under natural conditions. We exposed sparrows to short episodes of high predation risk by simulating the attack of a predator and assumed that the capture order of individuals was related to their escape capacity. The optimal strategy was the immediate escape response for all individuals. We found that first-year males were the best escapers. In support of the hypothesis, juvenile males gathered a better optimum of several morphological and physiological characters that related to capture order.

Factors Affecting Flock Size Mean and Variance in a Winter Population of House Sparrows (Passer Domesticus L.)

Behaviour ◽  
1980 ◽  
Vol 74 (1-2) ◽  
pp. 114-127 ◽  
Author(s):  
C.J. Barnard
Keyword(s):  
Ambient Temperature ◽  
Passer Domesticus ◽  
Time Of Day ◽  
Seed Density ◽  
Flock Size ◽  
House Sparrows ◽  
Feeding Site ◽  
Factors Affecting ◽  
Mean And Variance ◽  
Winter Population

Abstract1. In a field experiment with a winter population of house sparrows at a farm, flock size at a given feeding site appeared to be positively related to seed density. 2. The positive relationship between flock size and seed density resulted from individual birds spending longer in areas where seed density was high and from birds being recruited from elsewhere on the farm to experimental sites. 3. Mean flock size was positively related to and the variance of flock size negatively related to the time of day and both showed a tendency to be negatively correlated with the amount of human disturbance. Mean flock size was also positively related to ambient temperature and flock size variance negatively related to daylength. 4. The rate of fighting per bird increased with flock size and time of day but decreased with increasing ambient temperature. 5. The pattern of flock size distribution in house sparrows is compared to that in juncos and some differences between the two may be attributable to differences in the type of food supply and temperature range over winter.

Factors affecting the abundance of House Sparrows Passer domesticus in urban areas of southeast of Spain

Bird Study ◽  
2018 ◽  
Vol 65 (3) ◽  
pp. 404-416 ◽  
Author(s):  
Edgar Bernat-Ponce ◽  
José Antonio Gil-Delgado ◽  
Daniel Guijarro
Keyword(s):  
Urban Areas ◽  
Passer Domesticus ◽  
House Sparrows ◽  
Factors Affecting

Age and sex related differences in serum levels of unconjugated dehydroepiandrosterone and its sulphate in normal subjects

1997 ◽  
Vol 154 (1) ◽  
pp. 57-62 ◽  
Author(s):  
J Šulcová ◽  
M Hill ◽  
R Hampl ◽  
L Stárka
Keyword(s):  
Age Groups ◽  
Normal Subjects ◽  
Serum Levels ◽  
Significant Rise ◽  
First Year ◽  
Minimum Level ◽  
Age Related ◽  
First Year Of Life ◽  
Second Peak ◽  
Age And Sex

Abstract Dehydroepiandrosterone sulphate (DHEAS) and unconjugated dehydroepiandrosterone (DHEA) have been determined in the blood serum of normal subjects of both sexes from 1 month to 100 years of age. In total, 92 girls, 49 boys, 211 women and 110 men were investigated. The effects of age and sex on the levels of the hormones were measured. DHEAS levels declined rapidly during the first year of life and were maintained at a minimum level for 5 years. They increased significantly from 6 to 7 years of age and reached maximum levels in women at about 24 years and in men at about 30 years of age. They then declined rapidly in both sexes but the fall which occurred after 50 and 60 years of age respectively was only moderate. Age-related unconjugated DHEA levels were different. After the first month of life DHEA levels were relatively high and declined more slowly. The minimum level was observed in girls between 5 and 7 years and in boys between 5 and 9 years of age. A significant rise then began and levels reached a maximum in women as well as in men at about 20 years of age. In men levels then declined up to the age of 80. In women the DHEA levels declined during the next 15 years and from approximately 36 years of age they again rose significantly up to a second peak. A mild but significant decline then resumed. There was a difference in the levels of DHEA and DHEAS depending on sex. Unlike DHEAS, unconjugated DHEA was higher in women than in men. However, this difference was significant only in some age groups: during puberty (between 11 and 15 years of age), in the premenopausal period (between 36 and 45 years of age) and in the older group (after 60 years of age). Age- and sex-related dependencies were different between DHEAS and DHEA. They indicate the possible variable secretion and dynamics of their (inter)conversion. We have concluded that DHEA measurements cannot be a substitute for DHEAS and vice versa. Journal of Endocrinology (1997) 154, 57–62

Factors affecting intra- and inter-specific variations in the difference between alert distances and flight distances for birds in forested habitats

2002 ◽  
Vol 80 (7) ◽  
pp. 1212-1220 ◽  
Author(s):  
E Fernández-Juricic ◽  
M D Jimenez ◽  
E Lucas
Keyword(s):  
Bird Species ◽  
Passer Domesticus ◽  
Tree Height ◽  
Large Species ◽  
Pica Pica ◽  
Bare Ground ◽  
House Sparrows ◽  
Factors Affecting ◽  
Predator Prey ◽  
The Difference

Studies of escape from predators have usually focused on fleeing. We studied intra- and inter-specific variations in a previous level of decision-making during predator–prey encounters by determining the difference between the distance at which a predator is detected and the distance at which the prey flees from the predator (buffer distance). We measured buffer distances of four bird species (ground foragers) living in forested habitats (wooded recreational parks) to approaching humans. Buffer distances increased with group size and temperature, and this was probably related to dilution of the predation risk and a higher risk of heat stress, respectively. Buffer distances decreased with shrub and coniferous cover, probably because of increased visual obstruction, and increased with tree height, probably because of the increased security provided by taller trees. Grass cover increased buffer distances of wood pigeons (Columba palumbus) but decreased those of house sparrows (Passer domesticus) and magpies (Pica pica); this may be related to higher food availability, i.e., vegetation in grassy areas for wood pigeons and food left by humans in areas with bare ground for house sparrows and magpies. Buffer distances of blackbirds (Turdus merula) and house sparrows were greater in highly visited parks, which may be related to habituation. Finally, larger species showed greater buffer distances, landed farther away, used higher landing substrates (trees), and flew higher, probably because they need to ensure a certain margin of security from predators. Alternatively, the increased buffer distances of large species may be related to the increasing energy expenditure of flight. The buffer distance appears to be a good indicator of tolerance toward predators and (or) risk taken by prey after detecting predators.

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