Carl J. Erickson

Courtship Differences in Male Ring Doves: Avoidance of Cuckoldry?

Male ring doves exhibit less courtship and more aggressive behavior toward females that have recently associated with other males than to females that have been isolated. The difference in response may be related to the differing probability of cuckoldry.

Percussive foraging in the aye-aye, Daubentonia madagascariensis

Abstract A series of studies is described in which some of the sensory and motor capabilities used by the aye-aye, Daubentonia madagascariensis , in foraging for insect larvae are delineated. Although visual and olfactory cues may be of some aid, they are not necessary for successful location of larvae within woody sources. Rather, the aye-aye gently taps on wood surfaces to determine the location of cavities. Although the aye-aye can accurately locate cavities that contain no larvae or those containing inactive prey, significantly more cavities are opened when they contain active larvae. These observations suggest that this primate uses echolocation or a cutaneous sense to find cavities and can also detect the movements of insect larvae within the cavities.

Male Ring Dove Behavior and the Defense of Genetic Paternity

An initial experiment demonstrated that a female ring dove can store sperm for nearly 6 days after insemination; a second study indicated that if she loses her mate during this interval she actively solicits the parental aid of another. Yet, when males were paired with females that had recently associated with other males they exhibited more aggression and less courtship than when paired with females that had been isolated. The behavior of the male may provide, among other advantages, protection of his genetic paternity.

Some social and hormonal determinants of nest-building behaviour in the ring dove (Streptopelia risoria).

Two experiments were performed to evaluate some of the controlling factors in ring dove nest-building behaviour. In the first study six pairs of animals were observed each day until the first egg appeared. Behaviour was recorded during four intervals on each day in order to obtain estimates of diurnal changes in behaviour. Moreover, each pair was presented with a variety of nest-building materials in order to determine those kinds that would be most acceptable to the animals in subsequent studies. The birds showed striking diurnal changes in behaviour. Bow-cooing, aggressive pecking by the male, nest soliciting, time-in-the-nest, and allopreening exhibited a steady decline throughout the day. Nest-building activity reached a peak between one and seven hours after the lights came on in the morning and then declined throughout the remainder of the day. By contrast, copulatory behaviour, though infrequent in the morning hours, rose sharply in the late afternoon and reached a peak during the evening watch. Feeding and self-preening also increased slightly during the afternoon and evening. The ring doves also showed marked preferences in their choice of nest materials. Light-colored reed was preferred almost exclusively to dark-colored reed. Moreover, as nest construction progressed, there was a change in the type of material collected. During early building approximately equal numbers of pine needles as well as light and heavy reed were collected. As the nest neared completion, reed collection diminished and pine needles alone were collected. The resulting structure consisted of a base of several materials lined with pine needles alone. Observations in this first experiment suggested that gathering activity by the male was elicited by the presence of the female in the nest site. A second experiment was designed to examine this relationship. Twelve female ring doves were injected with progesterone and diethylstilboestrol while another twelve females served as oil-injected controls. Hormone-treated females were found to become more firmly established at the nest site during the first two days after introduction to a male. The males mated with these hormone-treated females engaged in more nest material gathering than did males mated with oil-treated females. It was concluded that gathering behaviour by the male is determined, at least in part, by relevant social cues from the female.

Proximity between the sexes in ring doves: Social bonds or surveillance?

Abstract Most bird species are monogamous, and in many instances the male provides a substantial contribution to the care of the young. Traditionally, the initial phase of the relationship between the sexes has been characterized in terms of pair formation and an increasing bond between the sexes. But recent formulations emphasize the role of guarding, surveillance, and other behavioural devices that protect the genetic relationship of the male to the offspring for which he cares. Ring doves were studied to determine whether the details of the relationship during the initial period are consistent with this latter view. Experiment 1 reveals that males remain in close proximity to their mates until the first egg is laid and the fertile period of the female ends; social contact then falls to a low level. Experiment 2 shows that when the female is removed during her fertile period, the male searches and calls more vigorously than does a female when her partner is absent. Finally, Experiment 3 demonstrates that it is visual contact rather than simply proximity that the male maintains during the fertile period of the female. These observations are consonant with the view that males maintain surveillance over their mates, but they do not exclude the possibility that the behaviour patterns might provide other benefits as well.

Tap-Scanning and Extractive Foraging in Aye-Ayes, Daubentonia madagascariensis

The trees on which aye-ayes forage contain complex communities of organisms. Aye-ayes appear to use tap-scanning behaviour, in combination with complex perceptual and inferential capabilities, to exploit these communities as a source of food. In doing so, they alter them, perhaps to their own advantage.

Pair bond maintenance in the ring dove (Streptopelia risoria)

Abstract Two experiments were carried out as follows: in the first males and females previously paired in the laboratory and isolated for periods up to 7 months were released into large outdoor cages in groups of three pairs each. In all cases the original pairs were re-established. In the second experiment females were offered a choice of former mates or strange males confined behind glass partitions in separate compartments. Twelve of fifteen females laid eggs near the former mate and performed more reproductive behaviour in his presence. These studies suggest that ring doves are capable of recognizing other individuals. Moreover, the pairing relationship is retained when physical contact is prevented, when individuals are isolated for extended periods, and when the original pairing relationship is experimenter-determined.

Percussive Foraging: Stimuli for Prey Location by Aye-Ayes (Daubentonia madagascariensis)

Aye-ayes (Daubentonia madagascariensis) use the thin middle finger to tap on wood in search of subsurface cavities containing insect larvae. When a cavity is located, they gnaw away wood until the prey can be extracted. Previous researchers suggested that acoustical cues reveal cavity location. We designed five studies to identify the cavity features that provide acoustical cues. When cavities were backfilled with gelatin or acoustical foam, excavation was still successful, suggesting that the reverberation of sound in air-filled cavities is not necessary for detection. Moreover, when the density of cavity content was varied, there was no difference in excavation frequency. On the other hand, a one-dimensional break in the subsurface wood was an effective stimulus for excavation. These studies suggest that a simple interface beneath the surface is sufficient to elicit excavation and that neither prey nor cavity nor even small air pockets are necessary to elicit the behavior. These results raise provocative questions as to how the aye-aye manages to forage efficiently.

Effects of mate familiarity on the courtship and reproductive success of the ring dove (Streptopelia risoria)

Abstract Sexually experienced male ring doves mated with former female mates exhibited lower levels of the bow-cooing display than did similarly experienced males paired with unfamiliar females. Pairs of unfamiliar animals were less successful in hatching eggs. However, there were no significant differences in the number of eggs laid, egg laying latency, or success of raising squabs.

Effects of septal lesions on the courtship behavior of male ring doves (Streptopelia risoria)

Abstract Male ring doves exhibit several androgen-dependent behavior patterns. Preliminary studies indicated that one of these, the nest-soliciting display, was selectively increased following septal lesions. In the present study castrated male ring doves received a septal lesion followed by daily intramuscular injections of 30 μg testosterone propionate (TP). Although one of the androgen-dependent displays, the bow-coo, was unaffected by the lesions, nest soliciting was significantly elevated during the period of hormone treatment. The restoration of nest-soliciting behavior in the males with septal lesions was even more rapid than that of unlesioned males receiving 200 μg TP/day, although after 12 days of treatment the performances of the latter came to approximate those of the males bearing septal lesions. Males that had received lesions in brain areas other than the septum were no more responsive to 30 μg of TP than were nonlesioned males receiving similar hormone treatment. It is suggested that the influence of the septum differs among the various androgen-dependent displays.