Territory Selection Research Articles

Territory occupancy and parental quality as proxies for spatial prioritization of conservation areas.

In order to maximize their fitness, individuals aim at choosing territories offering the most appropriate combination of resources. As population size fluctuates in time, the frequency of breeding territory occupancy reflects territory quality. We investigated the relationships between the frequency of territory occupancy (2002–2009) vs. habitat characteristics, prey abundance, reproductive success and parental traits in hoopoes Upupa epops L., with the objective to define proxies for the delineation of conservation priority areas. We predicted that the distribution of phenotypes is despotic and sought for phenotypic characteristics expressing dominance. Our findings support the hypothesis of a despotic distribution. Territory selection was non-random: frequently occupied territories were settled earlier in the season and yielded higher annual reproductive success, but the frequency of territory occupancy could not be related to any habitat characteristics. Males found in frequently occupied territories showed traits expressing dominance (i.e. larger body size and mass, and older age). In contrast, morphological traits of females were not related to the frequency of territory occupancy, suggesting that territory selection and maintenance were essentially a male's task. Settlement time in spring, reproductive success achieved in a given territory, as well as phenotypic traits and age of male territory holders reflected territory quality, providing good proxies for assessing priority areas for conservation management.

Стратегическое позиционирование городов и регионов

Situational analysis allows to combine ideas about marketing and management areas, at least at the strategic level, to look at regional development from the standpoint of Strategic Market Management. Especially great is its role in building the vision of the future territorial formation and selection of the main areas to achieve it. Actually, Strategic Market Management territorial development, based on the strategic positioning of the city or region combines three aspects of accounting and management: a category that successfully meets the needs of their environment (it is), the consumer segment (for whom it is) and benefits (it gives the consumer), — and is intended to reconcile the promises that gives elected in the strategic positioning of the brand of the city or region, with the actual investment strategy, which should provide a parallel implementation of the identified competitive advantages of the region or city through the implementation of strategic initiatives and project — specific drivers that are actively interested in the main consumers of media city or region — residents, businesses, investors. The results of such initiatives and projects, in turn, provide the efficiency and quality of reproduction and use of strategic resources of cities and regions, the best implementation of the three main functions as a place of residence, place of management and recreational facilities, and thus increase the competitiveness of the territorial entities and improve their strategic positioning.

Strategic Interaction Between Rebels and the State: A Study of the Maoist Conflict in Nepal

The “people's war” in Nepal during 1996–2006, led to two significant outcomes—the elimination of monarchy and political victory for the Maoists. These political outcomes raise important questions about the process of Maoist conflict in Nepal. While several studies on political conflict are concerned about “why” such conflicts happen, I focus on “how” the strategy of conflict unfolded in Nepal. In this article, I argue that strategic interaction between rebels and the state explain why the conflict led to negotiated settlement in Nepal. To discuss the sequence of rebel–state interaction, I introduce a game theoretic model. In addition, I show how territorial control, target selection, and levels of violence used by the rebels in comparison to the state are crucial in understanding the conflict process. The case study in this article analyzes the relevance of rebel–state interaction to reveal micro processes of political conflict and further suggests that negotiation can become an important tactical choice in resolving conflict.

Demographic conditions of the functioning of peasant families at the turn of the Middle Ages

Demographic conditions of the functioning of peasant families at the turn of the Middle Ages(Summary)The main aim of this paper is to present the possibilities of applying judicial sources to a demographic analysis of 15th- and 16th-century peasant families. The appearance of village court records is connected with the promulgation of German law on Polish lands and the emergence of the institution of local government headed by the bailiff, who together with peasant aldermen performed judicial duties. Over 70% of the village court records deal with the land market, rents, wills, matters of inheritance, loans and liens, criminal and moral cases, and disputes among neighbours. The subject of study in the present article is one of the oldest Polish village court records from the village of Trześniowa, 1409–1609, published by Helena Polaczkówna. The study focuses on three problems: the duration of the peasants’ economic activity, the size of families and territorial selection of spouses. The average duration (mean) for the investigated period was 24 years but the median was only 21, with visible discrepancies between particular subperiods. Peasants who remained active the longest were those who began their activity in the 15th century (mean – 25, median – 24). One hundred years later, this period was several years shorter (mean – 21.5; median – 20). The variations in the durations of peasants’ economic activity can also be observed in the social dimension. The average duration of the economic activity of members of the peasant elite (bailiffs, aldermen) amounted to 26 years (median – 25) and was significantly higher than among peasants who never performed any official functions. The average number of children registered in the court roll fluctuated throughout the period under investigation. In the case of 45 families whose children reached maturity in the 15th century, the mean was 1.7. In the following century the average rose to 3 children per family. However, among the offspring recorded in the court records there was a marked disproportion regarding gender, to the advantage of men, so women who are missing in the source should be added in order to achieve a balance. The observation of the reconstructed families in Trześniowa points to substantial differences in the number of children reaching adulthood in both groups of the peasant population. Throughout the entire investigated time period, in elite families the average number of children reaching adulthood amounted to 3.8 whereas among other peasants it was one child less. Trześniowa’s inhabitants married citizens of towns located at some distance from their family village – marriages were concluded with people living within 80 km of Trześniowa.

Chapter 8: Experimental determination of the response of Golden-cheeked Warblers (Setophaga chrysoparia) to road construction noise

Abstract Noise pollution can mask or distort bird songs, which can inhibit mating success, predator detection, and parental response to begging calls. We examined the impact of road construction noise on territory selection, reproductive success, and behavior of the federally endangered Golden-cheeked Warbler (Setophaga chrysoparia). To examine habituation and territory placement, we (1) used construction-noise playback to individual Golden-cheeked Warblers and evaluated occurrence of behavioral response as a function of distance from the roadway, and (2) established broadcast units that simulated construction noise to determine effects on territory selection. Among 88 surveys, six birds responded to construction-noise playback; all birds that responded were located ≥140 m from the road. We established three broadcast units per season in 2008 and 2009 to test for habituation. In each year, we placed broadcast units on the edges of randomly chosen territories identified during the previous field season. We...

Conspecific cues and breeding habitat selection in an endangered woodland warbler

1. Research on habitat selection has focused on the role of vegetative and geologic characteristics or antagonistic behavioural interactions. 2. Conspecifics can confer information about habitat quality and provide positive density-dependent effects, suggesting habitat selection in response to the presence of conspecifics can be an adaptive strategy. 3. We conducted a manipulative field experiment investigating use of conspecific location cues for habitat selection and consequent reproductive outcomes for the endangered golden-cheeked warbler (Setophaga chrysoparia). We investigated the response in woodlands across a range of habitat canopy cover conditions typically considered suitable to unsuitable and using vocal cues presented during two time periods: pre-settlement and post-breeding. 4. Warblers showed a strong response to both pre-settlement and post-breeding conspecific cues. Territory density was greater than four times higher in treatment sample units than controls. The magnitude of response was higher for cues presented during the pre-settlement period. Positive response to conspecific cues was consistent even in previously unoccupied areas with low canopy cover typically considered unsuitable, resulting in aggregations of warblers in areas generally not considered potential habitat. 5. Pairing and reproductive success of males was not correlated with canopy cover, as commonly thought. Pairing success and fledging success increased with increasing territory density suggesting that conspecific density may be more important for habitat selection decisions than the canopy cover conditions typically thought to be most important. These results suggest the range of habitat within which birds can perform successfully may be greater than is typically observed. 6. Our results suggest the territory selection process may not be substantially influenced by competition in some systems. Settlement in response to conspecific cues produced aggregations within larger areas of similar vegetative characteristics. Understanding what cues drive habitat selection decisions and whether these cues are correlated with habitat quality is critical for conserving fitness-enhancing habitats, avoiding creation of ecological traps, generating accurate predictions of species distributions and understanding how occupancy relates to habitat suitability.

Nest-site selection, territory quality and breeding performance in a Blue Tit Cyanistes caeruleus population

Patterns of territory selection and sources of variation for reproductive performance in a Blue Tit Cyanistes caeruleus population breeding in nest-boxes during years 2007 and 2008 in a holm oak forest are analyzed. Territory selection has been assessed as a function of two fixed effect factors: territory location (peripheral vs. interior in the nestbox patch) and nestbox type (entrance hole: 26 mm vs. 32 mm). Breeding density was independent of these factors. Pairs nesting in periphery nest-boxes and in small-holed nestboxes owned territories bigger than those nesting in interior and large-holed nestboxes, respectively. The breeding traits studied were laying date, clutch size, hatching success, fledgling success and breeding success. Egg laying was earlier in periphery territories and small-holed nestboxes. Between-year variation was a factor significantly affecting to all breeding traits. Clutch size declines in late clutches. Hatching success was higher in territories with more tree density. Although egg laying started earlier in some territories, the mean breeding success was similar in all of them. However, territories with the greatest contribution of individuals to the population were those with small-holed nestboxes. Breeding success in successful pairs had a tendency to be higher in pairs with late clutches and in those nesting in interior territories with large-holed nestboxes. Both decreased breeding success and total breeding failure were much more important in the second breeding year than in the first one. The high breeding density of Blue Tit, favored by the experimental design of nestbox plot, did not suggest significant variation between territories in terms of breeding success achieved. Implications for nestbox management are discussed.

Body temperature and territory selection by males of the speckled wood butterfly (Pararge aegeria): what makes a forest sunlit patch a rendezvous site?

1. Insects locate mobile resources like prey items or mates using either sit-and-wait (‘perching’) or active (‘patrolling’) searching strategies. The sit-and-wait strategy can be accompanied by defending and monopolising a site through territorial behaviour. 2. The present study focuses on the territorial perching behaviour in males of the speckled wood butterfly (Pararge aegeria L.). Recent studies suggested that the selection of territories (i.e. sunlit patches on the forest floor) is driven by structural characteristics of the site that affect male visual detection. However, given that adult butterflies are heliothermic organisms and that forests provide a diverse array of light environments, it seems likely that thermal aspects may also be used for territory selection. 3. We tested whether used and unused sunlit patches differed in thermal profile under field conditions in a Belgian woodland. We also used dummy butterflies to quantify variation in operative thoracic temperature and to calculate heating rates within (i.e. different vegetation structures) and between patches. 4. Sunlit patches occupied by a territorial male were larger, and were more frequently characterised by low vegetation structures compared with empty sunlit patches. It took longer to reach optimal thorax temperature (starting from a fixed suboptimal body temperature) in small patches compared with large patches. 5. We suggest that aspects of visual detection need to be combined with thermal aspects to fully understand territory selection in the speckled wood butterfly, as synergetic and/or trade-off effects of ambient temperature, solar radiation, and canopy/vegetation structure may be involved.

The impact of environmental factors on distribution of Scops Owl Otus scops in the wider area of Kras (SW Slovenia)

The impact of environmental factors on distribution of Scops Owl Otus scops in the wider area of Kras (SW Slovenia) The aim of the study was to determine the key environmental factors affecting Scops Owl Otus scops occurrence in the wider Kras plateau area (SW Slovenia, 665 km2). Scops Owl was systematically censused in 2006 (180 calling males) and in 2008 (167 calling males). Males were distributed either solitarily or clumped in groups, mostly situated in villages and its surroundings, indicating the species' synanthropic character. Crude densities were 0.3 males/km2 in 2006 and 2008, respectively, while ecological densities were 1.0 males/km2 in 2006 and 0.9 males/km2 in 2008. Population distribution remained roughly the same in both years, with the highest densities in the western and central parts of the Kras plateau, on Kraški rob and on Podgorski kras plateau. Habitat selection was analyzed at three spatial scales (regional, settlement and territory scales), based on spatial data layers (22 environmental variables), using Chi-square goodness-of-fit test and logistic regression. Results revealed that at the regional scale, Scops Owl preferably selected open habitats (extensively managed orchards, built-up areas, vineyards, permanent grasslands) and avoided dense forest and agricultural land with forest trees. As far as settlements were concerned, Scops Owl was more prone to select those that were more distant from the highway, with better preserved traditional agricultural landscape (with more hedgerows) and with higher average annual air temperature. In territory selection, Scops Owl occurrence was associated with longer distance from the highway, larger number of old buildings and higher landscape mosaics. The species seems to be threatened by traffic noise, habitat loss through abandonment and intensification of land and, potentially, by lack of breeding niches within settlements. Conservation measures should include the preservation of mosaic farmland, promotion of extensive agricultural practices, prevention of scrub and forest expansion, and maintenance of breeding niches (old trees, cavities in buildings).

Predation risk determines breeding territory choice in a Mediterranean cavity-nesting bird community

Non-direct effects of predation can be an important component of the total effect of predation, modulating animal population and community dynamics. The isolated effects of predation risk on the spatial organisation of the breeding bird community, however, remains poorly studied. We investigated whether an experimentally increased predation risk prior to reproduction affected breeding territory selection and subsequent reproductive strategies in three Mediterranean cavity-nesting birds, i.e., the little owl Athene noctua, European roller Coracias garrulus and scops owl Otus scops. We found that territories used the previous year were more likely to be re-occupied when they belonged to the safe treatment rather than to the risky treatment. The first choice of breeders of all three species was for safe territories over risky ones. When all breeding attempts in the season (i.e., final occupation) were considered, breeders also preferred safe to risky sites. In addition, little owls laid larger eggs in risky territories than in safe territories. Our study provides experimental evidence of a rapid preventive response of the three most abundant species in a cavity-nesting bird community to a short-term manipulation of predation risk. This response highlights the key role of the non-direct effects of predation in modulating avian community organisation.

Habitat selection as an antipredator behaviour in a multi‐predator landscape: all enemies are not equal

1. Breeding territory choice constitutes a crucial antipredator behaviour for animals that determines reproductive success and survival during the breeding season. On arrival to breeding grounds migrant prey face a multitude of 'waiting' predators already settled within the landscape. 2. We studied territory selection and reproductive investment of migrant pied flycatcher (Ficedula hypoleuca) relative to breeding pygmy owls (POs) (Glaucidium passerinum) and Tengmalm's owls (TOs) (Aegolius funereus). Diurnal POs present a greater predation threat to adult flycatchers (up to 80% songbirds in diet) compared with nocturnal TOs (up to 36%). 3. During territory selection, pied flycatchers strongly avoided POs (occupation: 42% in presence vs. 92% in absence of owl nest) but not TOs (80% vs. 75%). This suggests that flycatchers are able to distinguish between two potential predators, avoiding dangerous POs but not obviously responding to the less risky TOs. 4. Flycatchers responded to presence of PO nests with c. 4-day delay in the start of egg-laying. A significantly prolonged nest building period contributed to this potentially costly breeding delay. Flycatchers further significantly reduced initial reproductive investment in presence of POs by laying 8.2% smaller clutch sizes, even if laying date was controlled. No breeding delay and clutch size reduction was found relative to TO presence. 5. Our results highlight flexibility in breeding territory selection and reproductive strategies as antipredator responses to perceived risk in a multi-predator environment. This supports the idea that for prey, not all predators are equal.

From Wiens to Robel: A Review of Grassland‐Bird Habitat Selection

ABSTRACT Efforts to stabilize or increase grassland bird populations require identification of suitable habitat as a first step. Although the number of studies examining grassland‐bird habitat selection has increased substantially in recent years, much uncertainty exists regarding local‐scale habitat variables that researchers should consider. We reviewed 57 studies and identified important vegetation features correlated with grassland bird abundance, density, occurrence, and nest and territory selection. Our objectives were to 1) guide future studies of grassland‐bird habitat use by providing a reduced set of relevant vegetation characteristics, 2) challenge researchers to critically think about what variables to consider, and 3) highlight the need to include consistent definitions of terms used to describe grassland bird habitat. We identified 9 variables that were important predictors of habitat use by grassland birds: coverage of bare ground (important in 50% of the instances where it was included), grass (34% of instances), dead vegetation (33% of instances), forbs (31% of instances), and litter (29% of instances), along with an index of vegetation density (39% of instances) and volume (39% of instances), litter depth (36% of instances), and vegetation height (41% of instances). Only 25% of studies provided information on effects sizes and measures of variance. Furthermore, definitions of measured habitat variables were not consistent among studies. We provide definitions of the 9 important variables and implore authors to report effect size and measures of variance. Standardization of terms and reporting of meaningful results will facilitate replication of wildlife research and enhance our ability to recognize general patterns that emerge from observational studies of habitat use.

Vegetation influences patch occupancy but not settlement and dispersal decisions in a declining migratory songbird

Territorial clustering within larger, continuous patches of seemingly appropriate habitat could indicate that a species has additional, finer scale habitat requirements. Studying fine-scale (e.g., territory-level) habitat selection using methods that elucidate individual preferences may allow us to identify resources that influence species distributions. We examined breeding territory selection in the sagebrush Brewer’s Sparrow ( Spizella breweri Cassin, 1856) at the northern extent of its range to test for influences on fine-scale habitat selection. We used an information–theoretic approach to evaluate models relating a suite of vegetation characteristics to breeding habitat selection. We employed two methods: (1) assessment of patch occupancy at a territory scale and (2) examination of individual decisions relating to settlement and dispersal. We found that patch occupancy was most consistently predicted by models that included the cover of big sagebrush ( Artemisia tridentata Nutt.) with the greatest likelihood of occupancy at 20%–25% cover. However, assessment of settlement and dispersal decisions did not identify additional fine-scale preferences for other vegetation characteristics. Vegetation cover also did not influence breeding success, indicating that within the vegetation range found in Brewer’s Sparrow territory clusters, there is little benefit in basing individual settlement or dispersal decisions on vegetation cover.

Photoperiodic modulation of reproductive physiology and behaviour in the cichlid fish Cichlasoma dimerus

Timing of breeding to an optimal season is a requirement for a successful reproductive outcome in seasonally breeding species. Photoperiodic signals are capable of modifying the reproductive behaviour and reproductive systems in several vertebrate species. The cichlid fish Cichlasoma dimerus shows highly organized breeding activities and different social status. The aim of this study is to test whether C. dimerus reproductive behaviour (male aggressive behaviour and female choice) and reproductive physiology (GnRH3 morphometric parameters, pituitary hormones content and organ-somatic indexes) are modulated by photoperiod. Before spawning, dominant pairs were isolated and kept in opposite tanks of 20 l for one week, so they could see each other but not physically interact. Afterwards, a group was exposed for four weeks to a short photoperiod (8 h light:16 h dark) (short photoperiod exposed animals: SP) while another group was exposed to a long photoperiod (14 h light:10 h dark) (long photoperiod exposed animals: LP). Temperature was maintained constant. Behavioural experiments showed that male aggression related to territory selection and its defence is reduced in SP males. Further, SP females were never chosen. At the brain level we demonstrated that GnRH3 neuronal optical density of staining was reduced. Finally, at the pituitary level we showed that SP males showed low levels of β-LH, PRL and GH in the pituitary, and that SP females showed no significant differences in the pituitary content of any hormone. Taken all together these results suggest that in C. dimerus the photoperiod is a relevant environmental cue related to reproductive behaviour and physiology.

The attraction of the known: the importance of spatial familiarity in habitat selection in wapiti Cervus elaphus

Most studies of habitat selection by large herbivores focus on the resource availability and interactions with other species, but neglect the importance of an animal being familiar with an area due to past use. Yet, studies of the establishment and retention of territories, home ranges, birth sites, and feeding site choices in experimental settings have shown the importance of spatial familiarity at these scales. We used GPS locations of translocated wapiti Cervus elaphus, resource selection functions (RSF), and time‐to‐return to examine whether previous site use was important for selection of sites by wapiti in west‐central Alberta. To construct RSFs, we used logistic regression that included spatial familiarity (presence of a previous GPS location within a 50‐m radius) as well as estimates of herbaceous and shrub biomass, elevation, aspect, slope, and predation risk to wapiti from wolf predation, as dependent variables. We found that previous use had a strong positive relationship with subsequent site use, indicating that wapiti were not avoiding previously visited locations, as would be expected if memory of forage depletion (which we did not measure) determined response to familiar locations. Revisited sites were of higher quality, i.e. had more moderate terrain, higher forage, and lower predation risk, than sites that were not revisited, indicating that the selection of familiar locations was likely not the result of avoidance of unfamiliar locations. Finally, animals demonstrated preference for familiar locations that it had visited most recently, indicating that memory (which would decline with time) of higher site quality, rather than high quality alone, influenced selection for familiar locations. We conclude that spatial familiarity is important not only for large scale processes such as selection of home range and territory, but for smaller scale habitat selection and foraging as well.

Survival in a long-lived territorial migrant: effects of life-history traits and ecological conditions in wintering and breeding areas

Despite its key role in population dynamics and evolutionary ecology, little is known about factors shaping survival in long-lived territorial species. Here, we assessed several hypotheses that might explain variability in survival in a migratory Spanish population of a long-lived territorial species, the Egyptian vulture Neophron percnopterus, using a 16-year monitoring period and live-encounter histories of 835 individually marked birds. Cormack-Jolly-Seber capture-recapture models showed no evidence for effects of sex or nestling body condition on survival. However, the normalized difference vegetation index (NDVI; an indicator of primary productivity) of natal territories had positive effects on juvenile survival, indicating that environmental conditions experienced early in life can determine survival prospects. Survival increased with age (0.73 ± 0.02 in the first 2 years to 0.78 ± 0.03 in years 3 and 4) to later decrease when birds were five years old (0.60 ± 0.05), the age at which they acquire the adult plumage, abandon the communal lifestyle of juveniles, and may look for a breeding territory. At older ages, survival was higher for non-breeding (0.75 ± 0.02) and breeding adults (0.83 ± 0.02). Among the latter, birds that recruited into better territories had higher survival prospects. Age-specific variation in survival in this species may be related to behavioural changes linked to dispersal and recruitment into the breeding population, while survival prospects of adult birds strongly depend on breeding territory selection. These results suggest a tradeoff between recruiting soon, and thus reducing mortality costs of a long and extensive dispersal period, and trying to recruit into a good quality territory. Finally, annual survival rates for birds of all age classes were positively related with the NDVI in their African wintering grounds. Although this relationship was probably mediated by food availability, further research is needed to properly identify the limiting factors that are affecting trans-Saharan migrants, especially in light of global climate change.

The impacts of energy development noise playback on lek attendance and behavior in greater sagegrouse.

The spread of human development has caused a dramatic increase in noise across the landscape. Recent studies suggest that noise may negatively impact wildlife, yet little is known about the causes and consequences of this impact. Furthermore, most previous studies have not been designed to isolate noise impacts from other confounding factors. This study is investigating the impacts of energy development noise on greater sage grouse (Centrocercus urophasianus), a species of management concern across western North America. Sage grouse are declining in areas of energy development and circumstantial evidence suggests that noise is a cause of this decline. To test this hypothesis, control leks and leks with experimentally‐introduced energy development noise were monitored. Results from three seasons of experimental noise playback will be presented, comparing lek attendance, territory selection, and display behavior between noise and control leks. This is the first long‐term playback experiment investigating the chronic impacts of noise on any wild population, offering a unique opportunity to experimentally address noise impacts on avian behavior and breeding site selection while informing conservation efforts for this species.

Post‐breeding information gathering and breeding territory shifts in northern wheatears

1. Prospecting non-breeding individuals have been shown to collect information on breeding sites a year ahead of breeding, but whether experienced breeders prospect future breeding sites is less well-known. Using data on post-breeding movements and between-year site shifts from a long-term population study of the migratory northern wheatear (Oenanthe oenanthe L.), we investigated (1) whether breeding territory selection of experienced breeders was a two-step process, made partly in the post-breeding period and partly at the time of territory establishment in the subsequent year; (2) predictions of which factors and cues correlate to site shifts at these two selection periods; and (3) consequences of territory shifts. 2. Many wheatears stayed close to their breeding site during the post-breeding period, but about 20% shifted to new potential breeding sites. Males that shifted to a new post-breeding location were also more likely to shift territory between years. 3. Factors linked to site shifts differed in the two investigated episodes of site selection. Post-breeding site shifts were linked to an environmental predictor of individual fitness, which is also related to foraging conditions (i.e. wheatears moved from tall to short field layers). Post-breeding site shifts, however, were not more frequent among young and failed breeders which may benefit most from prospecting for alternative breeding sites. Instead, in line with predictions of improving breeding conditions between-year site shifts were more frequent among young (only males) and failed breeders, whereas the link to territory field layer height disappeared. 4. Young males occupied more attractive sites and were more likely to breed successfully in year t + 1, but this improvement could also be expected from random choice. 5. Our results suggest that even though site shifts are determined partly during the post-breeding period, post-breeding movements of experienced breeders may be costly, especially when the breeding site is also a good foraging and moulting site in the post-breeding season. Under such circumstances an individual's choice of breeding site may often be determined at arrival in the subsequent year.

Empirical evidence for ecological traps: a two-step model focusing on individual decisions

Ecological traps are poor quality habitats that are preferred by individuals and that cause standard indicators of habitat quality (e.g., density, age structure, order of settlement) to be misleading. A maladaptive choice of habitats may have detrimental effects on individual fitness and long-term population persistence. For conservation purposes, it is therefore critical to identify ecological traps. We discuss a recent review on the relationships between density, reproductive success and productivity at the patch level. We also discuss the concept of ecological traps and definitions of habitat quality and habitat preference. Based on recent literature on ecological traps, we argue that no study shows evidence of an ecological trap in its strict sense, i.e., a preference for sink and an avoidance of source habitat. This lack of evidence is partly due to poor measures of preference and individual fitness, and to an absence of studies at the individual level. We suggest a two-step protocol at the level of individuals to investigate ecological traps by linking: (1) habitat characteristics, i.e., potential cues used by individuals, to fitness, and (2) preference for specific habitat characteristics. This protocol is illustrated by a long-term study on breeding territory selection in Northern Wheatears (Oenanthe oenanthe) in Sweden. Using our protocol, we could determine at least in part why Wheatears show a mismatch between habitat preference and fitness. We conclude that there is an urgent need for more studies on individual habitat-selection decisions before we can find less labour-intensive ways to identify potential trap situations.

Habitat selection by Marsh Tits Poecile palustris in the UK

The Marsh Tit Poecile palustris is a small, hole‐nesting woodland passerine whose national population in the UK has declined by more than 50% in the last 25 years. To investigate possible causes for the species long‐term decline, we examined habitat selection by Marsh Tits at three scales. For individual foraging birds, winter time budgets and foraging behaviour, recorded using instantaneous sampling, differed little between Marsh and Blue Tits Cyanistes caeruleus, but Marsh Tits spent more time in the understorey and more time lower down in both the woodland canopy and the understorey. At the scale of breeding territories, the characteristics (numbers by size class, vegetation density, species richness) of trees and shrubs were compared using 100 × 10‐m sample transects of ten territories in each of four woods. The characteristics of the trees differed significantly between woods whilst those of the shrubs did not, suggesting that the characteristics of shrubs were more important in territory selection by Marsh Tits than were those of trees. Furthermore, in one of the four woods (Wytham Woods, Oxfordshire), Marsh Tits were largely absent from areas with dense tree canopy, but poor shrub cover. On a national scale, using data from 157 of the woodlands surveyed by the RSPB/BTO Repeat Woodland Bird Survey, Marsh Tit abundance in 2003/04 was found to be positively related to vegetation cover at heights corresponding to the shrub layer, especially at 2–4 m. These relationships were not apparent in data for the same woods for the 1980s, but shrub cover had increased substantially by 2003/04 and Marsh Tit abundance had increased in woods with the most cover in 2003/04. Thus, factors damaging the shrub layer, such as overgrazing by deer, shading out by canopy closure and managed clearance of shrub cover, may reduce the suitability of woodland for Marsh Tits. Habitat use by a closely related species, Willow Tit Poecile montanus, is also discussed.