Vocalisation Repertoire of Female Bluefin Gurnard (Chelidonichthys kumu) in Captivity: Sound Structure,Context and Vocal Activity

Fish vocalisation is often a major component of underwater soundscapes. Therefore, interpretation of these soundscapes requires an understanding of the vocalisation characteristics of common soniferous fish species. This study of captive female bluefin gurnard, Chelidonichthys kumu, aims to formally characterise their vocalisation sounds and daily pattern of sound production. Four types of sound were produced and characterised, twice as many as previously reported in this species. These sounds fit two aural categories; grunt and growl, the mean peak frequencies for which ranged between 129 to 215 Hz. This species vocalized throughout the 24 hour period at an average rate of (18.5 ± 2.0 sounds fish^-1 h^-1) with an increase in vocalization rate at dawn and dusk. Competitive feeding did not elevate vocalisation as has been found in other gurnard species. Bluefin gurnard are common in coastal waters of New Zealand, Australia and Japan and, given their vocalization rate, are likely to be significant contributors to ambient underwater soundscape in these areas.     

The vocal repertoires of the bush dog (Speothos venaticus), crab-eating fox (Cerdocyon thous), and maned wolf (Chrysocyon brachyurus)

The vocalizations of the bush dog (Speothos venaticus), crab-eating fox (Cerdocyon thous), and maned wolf (Chrysocyon brachyurus) were studied in a captive setting. The three species' repertoires were similar and included whines, long-distance calls, and growls. The whines and growls varied in amplitude, duration, and repetition rate; these variations and the frequencies of occurrence probably were influenced by both social organization and habitat characteristics. The bush dog, which lives in family groups and inhabits rain forests, had an elaborate whine-scream continuum that at close distances conveyed a wide range of moods. On the other hand, the maned wolf, which is solitary and frequents open pampas, used amplitude variations of the growl to signal hostile intentions over short, medium, and long distances.The long-distance vocalizations of the three species were the least variable in structure; the bush dog and crab-eating fox used the call to promote contact with separated pairmates or family members. Based on recordings during development, these two calls appeared to arise from the repetitive whine, a variant of the basic whine syllable. The maned wolf also had a contact-promoting howl, apparently an extended whine of high amplitude, but it was rarely recorded during the present study. More prominent was the maned wolf roar-bark, which functioned to space individuals over large distances, and appeared to be a growl of high amplitude.     

Acoustic and visual adaptations to predation risk: a predator affects communication in vocal female fish

Predation is an important ecological constraint that influences communication in animals. Fish respond to predators by adjusting their visual signaling behavior, but the responses in calling behavior in the presence of a visually detected predator are largely unknown. We hypothesize that fish will reduce visual and acoustic signaling including sound levels and avoid escalating fights in the presence of a predator. To test this we investigated dyadic contests in female croaking gouramis (Trichopsis vittata, Osphronemidae) in the presence and absence of a predator (Astronotus ocellatus, Cichlidae) in an adjoining tank. Agonistic behavior in T. vittata consists of lateral (visual) displays, antiparallel circling, and production of croaking sounds and may escalate to frontal displays. We analyzed the number and duration of lateral display bouts, the number, duration, sound pressure level, and dominant frequency of croaking sounds as well as contest outcomes. The number and duration of lateral displays decreased significantly in predator when compared with no-predator trials. Total number of sounds per contest dropped in parallel but no significant changes were observed in sound characteristics. In the presence of a predator, dyadic contests were decided or terminated during lateral displays and never escalated to frontal displays. The gouramis showed approaching behavior toward the predator between lateral displays. This is the first study supporting the hypothesis that predators reduce visual and acoustic signaling in a vocal fish. Sound properties, in contrast, did not change. Decreased signaling and the lack of escalating contests reduce the fish’s conspicuousness and thus predation threat.     

Innate threat-sensitive foraging: black-tailed deer remain more fearful of wolf than of the less dangerous black bear even after 100 years of wolf absence

Anti-predator behaviors often entail foraging costs, and thus prey response to predator cues should be adjusted to the level of risk (threat-sensitive foraging). Simultaneously dangerous predators (with high hunting success) should engender the evolution of innate predator recognition and appropriate anti-predator behaviors that are effective even upon the first encounter with the predator. The above leads to the prediction that prey might respond more strongly to cues of dangerous predators that are absent, than to cues of less dangerous predators that are actually present. In an applied context this would predict an immediate and stronger response of ungulates to the return of top predators such as wolves (Canis lupus) in many parts of Europe and North America than to current, less threatening, mesopredators. We investigated the existence of innate threat-sensitive foraging in black-tailed deer. We took advantage of a quasi-experimental situation where deer had not experienced wolf predation for ca. 100 years, and were only potentially exposed to black bears (Ursus americanus). We tested the response of deer to the urine of wolf (dangerous) and black bear (less dangerous). Our results support the hypothesis of innate threat-sensitive foraging with clear increased passive avoidance and olfactory investigation of cues from wolf, and surprisingly none to black bear. Prey which have previously evolved under high risk of predation by wolves may react strongly to the return of wolf cues in their environments thanks to innate responses retained during the period of predator absence, and this could be the source of far stronger non-consumptive effects of the predator guild than currently observed.     

Comparative Patterns of Predation by Cougars and Recolonizing Wolves in Montana's Madison Range

Abstract: Numerous studies have documented how prey may use antipredator strategies to reduce the risk of predation from a single predator. However, when a recolonizing predator enters an already complex predator—prey system, specific antipredator behaviors may conflict and avoidance of one predator may enhance vulnerability to another. We studied the patterns of prey selection by recolonizing wolves (Canis lupus) and cougars (Puma concolor) in response to prey resource selection in the northern Madison Range, Montana, USA. Elk (Cervus elaphus) were the primary prey for wolves, and mule deer (Odocoileus hemionus) were the primary prey for cougars, but elk made up an increasingly greater proportion of cougar kills annually. Although both predators preyed disproportionately on male elk, wolves were most likely to prey on males in poor physical condition. Although we found that the predators partitioned hunting habitats, structural complexity at wolf kill sites increased over time, whereas complexity of cougar kill sites decreased. We concluded that shifts by prey to structurally complex refugia were attempts by formerly naïve prey to lessen predation risk from wolves; nevertheless, shifting to more structurally complex refugia might have made prey more vulnerable to cougars. After a change in predator exposure, use of refugia may represent a compromise to minimize overall risk. As agencies formulate management strategies relative to wolf recolonization, the potential for interactive predation effects (i.e., facilitation or antagonism) should be considered.     

Acoustic defence in an insect: characteristics of defensive stridulation and differences between the sexes in the tettigoniid Poecilimon ornatus (Schmidt 1850)

Many insects exhibit secondary defence mechanisms upon contact with a predator, such as defensive sound production or regurgitation of gut contents. In the tettigoniid Poecilimon ornatus, both males and females are capable of sound production and of regurgitation. However, wing stridulatory structures for intraspecific acoustic communication evolved independently in males and females, and may result in different defence sounds. Here we investigate in P. ornatus whether secondary defence behaviours, in particular defence sounds, show sex-specific differences. The male defence sound differs significantly from the male calling song in that it has a longer syllable duration and a higher number of impulses per syllable. In females, the defence sound syllables are also significantly longer than the syllables of their response song to the male calling song. In addition, the acoustic disturbance stridulation differs notably between females and males as both sexes exhibit different temporal patterns of the defence sound. Furthermore, males use defence sounds more often than females. The higher proportion of male disturbance stridulation is consistent with a male-biased predation risk during calling and phonotactic behaviour. The temporal structures of the female and male defence sounds support a deimatic function of the startling sound in both females and males, rather than an adaptation for a particular temporal pattern. Independently of the clear differences in sound defence, no difference in regurgitation of gut content occurs between the sexes.     

Prey Responses to Predator's Sounds: A Review and Empirical Study

Many animals assess their risk of predation by listening to and evaluating predators' vocalizations. We reviewed the literature to draw generalizations about predator discrimination abilities, the retention of these abilities over evolutionary time, and the potential underlying proximate mechanisms responsible for discrimination. Broadly, we found that some prey possess an ability to respond to a predator after having been evolutionarily isolated from a specific predator (i.e., predators are allopatric) and that some prey are predisposed to respond to certain types of predators that they coevolved with but without having ecological experience. However, these types of studies are lacking, and relatively, few studies have examined predator discrimination abilities in ungulates. To begin addressing these knowledge gaps, we performed field experiments on Mule deer (Odocoileus hemionus) in which we investigated the ability of deer to discriminate among familiar predators [coyotes (Canis latrans) and mountain lions (Puma concolor)] and an evolutionary relevant predator with which deer have had no recent exposure [locally extinct wolves (Canis lupus)]. We found that Mule deer respond to and discriminate among predators based on predator vocalizations and have retained an ability to respond to wolves that have been extinct from the study area since the early 20th century. Previous playback studies have shown that responses vary among human‐habituated and non‐habituated populations and differ according to human proximity. Deer greater than 0.5 km from human residences allocated more time to heightened responses both before and after stimulus playback. Our findings may help predict how prey–predator interactions may change as a result of the recovering wolf population with a basis in ecological and evolutionary experience in predator discrimination and desensitization.     

Mesopredator suppression by an apex predator alleviates the risk of predation perceived by small prey

Predators can impact their prey via consumptive effects that occur through direct killing, and via non-consumptive effects that arise when the behaviour and phenotypes of prey shift in response to the risk of predation. Although predators'' consumptive effects can have cascading population-level effects on species at lower trophic levels there is less evidence that predators'' non-consumptive effects propagate through ecosystems. Here we provide evidence that suppression of abundance and activity of a mesopredator (the feral cat) by an apex predator (the dingo) has positive effects on both abundance and foraging efficiency of a desert rodent. Then by manipulating predators'' access to food patches we further the idea that apex predators provide small prey with refuge from predation by showing that rodents increased their habitat breadth and use of ‘risky′ food patches where an apex predator was common but mesopredators rare. Our study suggests that apex predators'' suppressive effects on mesopredators extend to alleviate both mesopredators'' consumptive and non-consumptive effects on prey.     

Aggressive howling in wolves

During two studies that investigated the responses of wolf packs to either human simulations or pre-recorded playbacks of wolf, Canis lupus, howling, single adult wolves from five different packs approached my location and howled on a total of six occasions. The howls uttered by these close-approaching wolves were significnatly deeper in pitch than comparable samples of howls recorded from animals that did not approach. In addition, howls of two of the five animals differed in structure from most of the other howls recorded during both studies. These close-approach howls were characterized by the presence of harmonically unrelated frequency sidebands near the end of the howl. This feature was rate in howls recorded during occasions when wolves kept their distance. These results indicate that the structure of wolf howling during aggressive interactions with strange wolves follows Morton's (1977) motivation-structural rules, which state that natural selection will favour the use of low-frequency, harsh sounds by hostile animals. This relationship follows from the physical constraints of vocal production: animals of larger size can produce sounds of lower pitch and harsher tonal quality. As body size is a primary determinant in the outcome of aggressive interactions, vocalizations signalling size (i.e.low-pitched, harsh sounds) will be of selective value for individuals engaged in aggressive interactions.     

Does the type of exercise affect tryptophan catabolism in horses?

Tryptophan (Trp) is an essential amino acid which metabolises via the kynurenine pathway to generate a number of bioactive substances referred to as kynurenines. Among those are 3-hydroxykynurenine (3-HKyn) and quinolinic acid, which are neurotoxic, as well as kynurenic acid (Kyna) and xanthurenic acid (XA), which, similarly to nicotinamide (NAm), show neuroprotective and anti-depressive effects. Routine exercise is known to modulate Trp metabolism in skeletal muscle and is thus believed to reduce the risk of depressive states in humans and laboratory animals. Analogously, it was hypothesised that exercise can influence Trp metabolism in horses as well. The aim of this study was to evaluate the influence of two different types of exercise on Trp metabolism in horses of the same breed. A total of 32 purebred Arabian horses were involved in the study. The 22 three-year-old racehorses were subjected to short-time intense exercise. Ten other horses were made to perform endurance competitions at a distance of 80 km. Blood samples were collected at rest and following the end of the exercise period. Plasma concentrations of Trp, kynurenine (Kyn), Kyna, 3-HKyn, XA and NAm were determined using Ultra-High Performance Liquid Chromatography-Electrospray Ionisation-Tandem Mass Spectrometry. Short-time intense exercise led to an increase in plasma concentrations of Kyn, Kyna and XA. The endurance effort induced an increase in Kyna and a decrease in Trp and NAm levels. Both types of exercise, short-time intensive exercise and endurance exercise induced an increase in Trp metabolites, especially Kyna, and did not induce an increase in Trp level. Thus, from a pathophysiological perspective of the kynurenine pathway’s influence on mental state, both types of exercise induced beneficial effects in horses.     

Nestling presence affects the anti-predator response of adult superb fairy-wrens (Malurus cyaneus)

Nest predation accounts for the majority of nesting failure, and hence there has been strong selection on behaviour to reduce nest predation, including patterns of nest defence. Here, we test risk-taking behaviour to experimentally placed predators in the presence or absence of nestlings. We use the superb fairy-wren (Malurus cyaneus) to test the prediction that vigilance will be comparable with and without nestlings, but that alarm vocalisations will increase when nestlings are present. We found support for both predictions. Adult vigilance of predators was comparable with and without nestlings. Alarm vocalisation intensity was predicted by predator type and nestling presence, and was highest to the snake model in the presence of nestlings. These results point to selection for differentiated nest defence response in relation to predator type and the presence or absence of nestlings.     

Predator odour per se does not frighten domestic horses

Horses frequently react nervously when passing animal production farms and other places with distinctive smells, leading riders to believe that horses are innately frightened by certain odours. In three experiments, we investigated how horses respond to (1) urine from wolves and lions, (2) blood from slaughtered conspecifics and fur-derived wolf odour, and (3) a sudden auditory stimulus in either presence or absence of fur-derived wolf odour. The experiments were carried out under standardised conditions using a total of 45 naïve, 2-year-old horses. In the first two experiments we found that horses showed significant changes in behaviour (Experiments 1 and 2: increased sniffing; Experiment 2 only: increased vigilance, decreased eating, and more behavioural shifts), but no increase in heart rate compared to controls when exposed to predator odours and conspecific blood in a known test environment. However, the third experiment showed that exposure to a combination of wolf odour and a sudden stimulus (sound of a moving plastic bag) caused significantly increased heart rate responses and a tendency to a longer latency to resume feeding, compared to control horses exposed to the sudden stimulus without the wolf odour. The results indicate that predator odour per se does not frighten horses but it may cause an increased level of vigilance. The presence of predator odour may, however, cause an increased heart rate response if horses are presented to an additional fear-eliciting stimulus. This strategy may be adaptive in the wild where equids share habitats with their predators, and have to trade-off time and energy spent on anti-predation responses against time allocated to essential non-defensive activities.     

Comparison of Thoroughbred and Arabian horses using RAPD markers

We compared pools of DNA from 10 Thoroughbred horses and 10 Arabian horses for the presence of randomly amplified polymorphic DNA (RAPD) markers which might be useful in distinguishing between the breeds. Using 212 decamer oligonucleotides and our polymerase chain reaction (PCR) conditions, 173 of the primers produced scoreable bands. The number of bands ranged from 0 to 9 with an average of 3·6. In family studies using 11 arbitrarily selected primers, five of the 11 primers produced polymorphic bands which exhibited Mendelian inheritance as dominant markers. When comparing the pooled DNA from Thoroughbred and Arabian horses we found 10 primers which identified markers present in the pooled DNA from one breed but absent in the pool from the other breed. Testing individual horses revealed that only two markers were wholly absent for one group while being present among members of the other. Primer UBC-85 (5′-GTGCTCGTGC-3′) detected a pair of markers absent in Thoroughbred horses but present among 11 of 31 Arabian horses. These markers were 1500 and 1700 base pairs (bp) long and designated UBC-85^C and UBC-85^D, respectively. Primer UBC-126 (5′-CTTTCGTGCT-3′) detected a 1000 bp marker (designated UBC-126^C) absent in 20 of 20 Thoroughbred horses but present in 31 of 31 Arabian horses. UBC-126^C would be particularly effective for breed comparisons, especially if the DNA band were cloned, sequenced and an allelic marker present in Thoroughbred horses but rare or absent among Arabian horses was identified. The distribution of such markers among other horse breeds might be useful to infer relationships among breeds. These kinds of markers may also be useful in detecting unwanted crossbreeding between two horse breeds.     

The influence of domestic piglets' (<Emphasis Type="Italic">Sus scrofa</Emphasis>) age and test experience on the preference for the replayed maternal nursing vocalisation in a modified open-field test

The nursing vocalisation of lactating sows is an important part of the complex nursing and suckling behaviour of domestic pigs (Sus scrofa). It helps to lead the young through the several phases of a nursing episode. A total of 135 suckling piglets were investigated regarding their reactions to different vocalisations and sounds successively replayed in combined choice/open-field experiments. Two piglet samples were used to determine the impact of age (sample 1: weeks 1 and 5, n=93) and previous test experience of naive older piglets (sample 2: week 5, n=42) on their behavioural responses. In the 1st week after birth, the nursing vocalisation of sows released an initial generalised approach and contact response in the young, indicating high motivation to gain nutritional or social support. Close to the sound source, the piglets then strongly preferred the nursing vocalisation produced by their own mothers compared to that produced by another, unrelated and unfamiliar sow, or an artificial sound composed of similar frequencies as the nurse grunting, or a control without sound. However, at the end of the suckling period (5-week-old piglets) no clear differences in the reactions to the sounds could be identified. Moreover, the lack of a clear response at week 5 seems largely independent of any earlier test experience of the piglets. As well in the 1st as in the 5th week the piglets showed a decrease in open-field activity when sow grunting was present, indicating that the replay of the nursing vocalisation might have some calming effect. Communicated by K. Kotrschal     

Interacting Effects of Leg Autotomy and Exposure to Predator Cues on Survival in A Wolf Spider (<Emphasis Type="Italic">Pardosa valens</Emphasis>)

Chemical cues from predators (kairomones) are used by many aquatic and terrestrial animals when deciding on behavioral responses to predation threats. These responses may also be affected by the animal’s physiological state (e.g., nutrition level, parasitism, or prior injury), which could alter normal responses to kairomones. In this study, we examined effects of leg autotomy (the voluntary sacrifice of a leg) on subsequent responses to predator chemical cues in females of the riparian-zone wolf spider Pardosa valens. In a fully-crossed design, spiders with all legs intact or with one leg removed were exposed to one of two cue treatments for 90 min: a control (no predator cue) or one with chemical cues (silk and excreta) from a larger sympatric wolf spider, Rabidosa santrita. We then introduced an R. santrita into each container, and recorded subsequent survival of P. valens. Survivorship was significantly higher for individuals previously exposed to predator cues than for those in the control group; however, autotomy had no effect on survivorship, which was similar for both intact and autotomized spiders in both the predator-cue and control treatments. In addition, although P. valens were more likely to be found off the substrate than on it when the predator was added in each of the four treatment pairings, this initial position did not influence survivorship. These results therefore indicate that P. valens can behaviorally respond to predator kairomones in ways that reduce their risk of predation, but that this response is unaffected by the prior sacrifice of a leg.     

Mobility of moose—comparing the effects of wolf predation risk,reproductive status,and seasonality

In a predator–prey system, prey species may adapt to the presence of predators with behavioral changes such as increased vigilance, shifting habitats, or changes in their mobility. In North America, moose (Alces alces) have shown behavioral adaptations to presence of predators, but such antipredator behavioral responses have not yet been found in Scandinavian moose in response to the recolonization of wolves (Canis lupus). We studied travel speed and direction of movement of GPS‐collared female moose (n = 26) in relation to spatiotemporal differences in wolf predation risk, reproductive status, and time of year. Travel speed was highest during the calving (May–July) and postcalving (August–October) seasons and was lower for females with calves than females without calves. Similarly, time of year and reproductive status affected the direction of movement, as more concentrated movement was observed for females with calves at heel, during the calving season. We did not find support for that wolf predation risk was an important factor affecting moose travel speed or direction of movement. Likely causal factors for the weak effect of wolf predation risk on mobility of moose include high moose‐to‐wolf ratio and intensive hunter harvest of the moose population during the past century.     

Conservation of wildlife populations: factoring in incremental disturbance

Progressive anthropogenic disturbance can alter ecosystem organization potentially causing shifts from one stable state to another. This potential for ecosystem shifts must be considered when establishing targets and objectives for conservation. We ask whether a predator–prey system response to incremental anthropogenic disturbance might shift along a disturbance gradient and, if it does, whether any disturbance thresholds are evident for this system. Development of linear corridors in forested areas increases wolf predation effectiveness, while high density of development provides a safe‐haven for their prey. If wolves limit moose population growth, then wolves and moose should respond inversely to land cover disturbance. Using general linear model analysis, we test how the rate of change in moose (Alces alces) density and wolf (Canis lupus) harvest density are influenced by the rate of change in land cover and proportion of land cover disturbed within a 300,000 km² area in the boreal forest of Alberta, Canada. Using logistic regression, we test how the direction of change in moose density is influenced by measures of land cover change. In response to incremental land cover disturbance, moose declines occurred where <43% of land cover was disturbed; in such landscapes, there were high rates of increase in linear disturbance and wolf density increased. By contrast, moose increases occurred where >43% of land cover was disturbed and wolf density declined. Wolves and moose appeared to respond inversely to incremental disturbance with the balance between moose decline and wolf increase shifting at about 43% of land cover disturbed. Conservation decisions require quantification of disturbance rates and their relationships to predator–prey systems because ecosystem responses to anthropogenic disturbance shift across disturbance gradients.     

What Cues Do Ungulates Use to Assess Predation Risk in Dense Temperate Forests?

Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in the Białowieża Primeval Forest (Poland), whether perceived predation risk in red deer (Cervus elaphus) and wild boar (Sus scrofa) is related to habitat visibility or olfactory cues of a predator. We used camera traps in two different set-ups to record undisturbed ungulate behavior and fresh wolf (Canis lupus) scats as olfactory cue. Habitat visibility at fixed locations in deciduous old growth forest affected neither vigilance levels nor visitation rate and cumulative visitation time of both ungulate species. However, red deer showed a more than two-fold increase of vigilance level from 22% of the time present on control plots to 46% on experimental plots containing one wolf scat. Higher vigilance came at the expense of time spent foraging, which decreased from 32% to 12% while exposed to the wolf scat. These behavioral changes were most pronounced during the first week of the experiment but continuous monitoring of the plots suggested that they might last for several weeks. Wild boar did not show behavioral responses indicating higher perceived predation risk. Visitation rate and cumulative visitation time were not affected by the presence of a wolf scat in both ungulate species. The current study showed that perceived predation risk in red deer and wild boar is not related to habitat visibility in a dense forest ecosystem. However, olfactory cues of wolves affected foraging behavior of their preferred prey species red deer. We showed that odor of wolves in an ecologically equivalent dose is sufficient to create fine-scale risk factors for red deer.     

Foraging decisions of North American beaver (<Emphasis Type="Italic">Castor canadensis</Emphasis>) are shaped by energy constraints and predation risk

Foraging herbivores have to trade-off between energy requirements and predator avoidance. We aimed to study the relative roles of these factors in beavers (Castor canadensis) when foraging on land. We hypothesized that beavers were able to assess the risk of predation by using two main cues: the distance from the water and the presence or absence of predator odors. First, we studied the food selection of beavers in relation to distance from the water in natural settings. The transects were made at beaver ponds, and the diameter, species, and distance from the shore of intact and beaver-cut trees were recorded. Secondly, we placed rows of aspen sticks (Populus tremula) perpendicular to the shore around beaver ponds, and treated each row with a neutral, alien, or wolf odor. We found that aspen, downy birch (Betula pubescens), and speckled alder (Alnus incana) were the preferred tree species. More of these species were cut close to the shore, and cut trees were smaller further away from the shore, except in the case of aspen. In the experiment, most of the aspen sticks were taken close to the shore. As predicted, beavers took less aspen sticks in rows treated with wolf odor than water. As the predator odor did not affect the foraging distance from the shore, it is likely that our observation that foraging was the most intense close to shore is due to energetic constraints. However, predation risk probably affects the decision whether to forage on the land in the first place.     

Is hissing behaviour of incubating great tits related to reproductive investment in the wild?

Anti-predator behaviour of breeding animals is a complex trait that depends on current reproductive investment as well as individual differences in risk-taking propensities. In response to nest predation, many bird species produce specific sounds, such as the hissing calls in incubating great tits (Parus major), that may provoke an acoustic startle response in the predator. However, it is still unclear whether the propensity of incubating females to produce hissing calls towards nest predators depends on the reproductive investment. With our 3-year study, we show that response type (females that do not hiss versus females giving hissing calls) to a potential nest predator, the woodpecker, is a repeatable trait. We found no differences in the studied reproductive traits between hissing and non-hissing birds. Interestingly, among hissing birds, fast-responding females started egg-laying earlier than slow-responding ones. Among non-hissing birds, heavier birds initiated clutches earlier. We also revealed that hissing birds breed in areas with decreased nest-box occupancy, suggesting either that they potentially select different areas to breed or that territory size is larger as a result of hissing birds being more aggressive. These findings demonstrate that response type is not related to the early reproductive value of the brood across distinct behavioural groups. However, our results do suggest that non-hissing and hissing females differ in terms of individual quality or dominance or personality related aspects.