Modes of perceiving and processing information in birdsong (Agelaius phoeniceus, Molothrus ater, and Homo sapiens).

1987 ◽  
Vol 101 (4) ◽  
pp. 355-366 ◽  
Author(s):  
Joan M. Sinnott
1991 ◽  
Vol 69 (8) ◽  
pp. 2093-2099 ◽  
Author(s):  
David M. Scott

I present data on the time of day of oviposition for 16 species of icterines to evaluate the idea that laying exceptionally early in the morning by the brood parasite, the Brown-headed Cowbird (Molothrus ater), is a specialization for parasitism. This cowbird, the earliest known layer among icterines, typically lays before sunrise (sunrise −9.14 ± 2.52 (SE) min, n = 36). Another brood parasite, the Shiny Cowbird (Molothrus bonariensis), also sometimes lays before sunrise. The best-known nonparasitic icterines, the Red-winged Blackbird (Agelaius phoeniceus) and the Common Grackle (Quisacalus quiscula), lay shortly after sunrise. Fragmentary records show that several other icterines lay within an hour or so after sunrise. Data are inadequate to conclude that early laying by Brown-headed Cowbirds has arisen as an adaptation for parasitism. The Brown-headed Cowbird at London, Ontario, lays earlier than most local passerines, as is shown by new data on oviposition by seven host species arranged in order of increasing lateness of oviposition: Agelaius phoeniceus, Dendroica petechia, Melospiza melodia, Cardinalis cardinalis, Vireo olivaceus, Dumetella carolinensis, and Turdus migratorius.


Behaviour ◽  
1992 ◽  
Vol 123 (1-2) ◽  
pp. 84-105 ◽  
Author(s):  
Spencer G. Sealy ◽  
Diane L. Neudorf

AbstractFour host species of the parasitic brown-headed cowbird (Molothrus ater) were exposed to taxidermic mounts of a female cowbird, fox sparrow (Passerella iliaca), and common grackle (Quiscalus quiscula) at their nests during their egg-laying or nestling stage. Red-winged blackbirds (Agelaius phoeniceus), a species that accepts cowbird eggs laid in their nests, responded more aggressively to cowbird models early in their nesting cycle, indicating that they recognized the unique threat the cowbird posed. Gray catbirds (Dumetella carolinensis), northern orioles (Icterus galbula), and cedar waxwings (Bombycilla cedrorum) can remove cowbird eggs from their nests and for the most part they responded similarly to cowbird models and the "nonthreatening control," i.e. a fox sparrow. Cedar waxwings were nonaggressive to all the models and may rely on concealment to protect their nests from enemies. Removal of cowbird eggs by puncture ejection is more risky than grasp ejection. Despite this, orioles and waxwings (puncture ejectors) were not significantly more aggressive to cowbird models at egg laying than catbirds (grasp ejectors). Responses of the three rejector species toward the cowbird model did not change over the nesting cycle, indicating further that they do not recognize cowbirds as a unique threat. Rejector species may not recognize cowbirds because they have little experience with them. With the exception of waxwings, all of the hosts recognized the grackle as an enemy and increased their levels of defence from the laying to nestling stages. Three of the host-species did not simply respond in a generalized manner to any intruder at their nests but indeed recognized specific enemies. Considerable interspecific variability exists amongst the four species in defensive behaviours, which may reflect their different nesting habitats.


1987 ◽  
Vol 65 (3) ◽  
pp. 605-607 ◽  
Author(s):  
Katherine E. Muma ◽  
C. Davison Ankney

To investigate variation in egg weight and composition we collected and analyzed 38 Red-winged Blackbird (Agelaius phoeniceus) eggs. The composition of Red-winged Blackbird eggs was very similar to that reported for Brown-headed Cowbird (Molothrus ater) eggs. Egg weight is a good predictor of total energy (kJ) in blackbird eggs as those two variables were highly correlated (r2 = 0.66). Weight of Red-winged Blackbird eggs did not change over the breeding season.


2021 ◽  
Vol 9 ◽  
Author(s):  
Shelby L. Lawson ◽  
Janice K. Enos ◽  
Sharon A. Gill ◽  
Mark E. Hauber

Referential alarm calls that denote specific types of dangers are common across diverse vertebrate lineages. Different alarm calls can indicate a variety of threats, which often require specific actions to evade. Thus, to benefit from the call, listeners of referential alarm calls must be able to decode the signaled threat and respond to it in an appropriate manner. Yellow warblers (Setophaga petechia) produce referential “seet” calls that signal to conspecifics the presence of nearby obligate brood parasitic brown-headed cowbirds (Molothrus ater), which lay their eggs in the nests of other species, including yellow warblers. Our previous playback experiments have found that red-winged blackbirds (Agelaius phoeniceus), a species also parasitized by brown-headed cowbirds, eavesdrop upon and respond strongly to yellow warbler seet calls during the incubation stage of breeding with aggression similar to responses to both cowbird chatters and predator calls. To assess whether red-winged blackbird responses to seet calls vary with their own risk of brood parasitism, we presented the same playbacks during the nestling stage of breeding (when the risk of brood parasitism is lower than during incubation). As predicted, we found that blackbirds mediated their aggression toward both cowbird chatter calls and the warblers’ anti-parasitic referential alarm calls in parallel with the low current risk of brood parasitism during the nestling stage. These results further support that red-winged blackbirds flexibly respond to yellow warbler antiparasitic referential calls as a frontline defense against brood parasitism at their own nests.


2021 ◽  
pp. 9-19
Author(s):  
O. DZOBAN

It is proposed to consider a digital person as the latest stage of human development as a major object and subject of information relations in the information society at the latest stages of its development; as a postmodern type of a homo sapiens capable of processing information, creating new information phenomena, interconnections and structures. It is substantiated that the transition to a digital person occurred due to convergence of technologies of artificial intelligence, machine training and powerful databases capable of using an unlimited amount of information for its processing, classification and multiple use. The attention is drawn to the fact that a digital person is, first of all, a person of new moral values, which immerses in the virtual reality of simulations and increasingly perceives the world as a digital game environment, realizing its conventionality, controllability of its parameters and the possibility of exiting it.


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