Microhabitat suitability as a tool to improve the success rate of a translocation or reintroduction,case‐study of the bullhead (Cottus perifretum) in Flanders,Belgium

Microhabitat suitability models are useful tools to enhance the reintroduction success of fish. Since 2008, a translocation and reintroduction program has been carried out in Flanders to prevent substantial loss of genetic variability in the Cottus perifretum (bullhead) population, and to meet the goals set by the Habitat Directive. To this end, habitat suitability of potential headstreams was assessed on a macrohabitat and microhabitat scale prior to the reintroduction. On a macrohabitat scale, water quality, habitat structure, food availability, and fish community were screened. Based on microhabitat models for bullhead in the summer period, microhabitat suitability was assessed in headstreams where macrohabitat characteristics showed a high potential for success. Both macro‐ and microhabitat assessment showed that reintroduction of bullheads in the Nellebeek, Bruelbeek, and Mollendaalbeek would most likely lead to self‐sustaining populations. For the Sint‐Annabeek, the microhabitat suitability model, considering depth and stream velocity, estimates that 7.5–9.5% of the headstream is suitable for bullhead. However, when substratum is taken into account, the microhabitat suitability index shows that only 4.3–5.8% of the brook is suitable. The current habitat quality and quantity in the Sint‐Annabeek is estimated to support a mean total population of 812 bullheads. However, the microhabitat suitability can be substantially improved by the artificial deposition of medium‐sized gravel (5–50 mm) and large gravel (50–100 mm). By doing so, the mean estimated population size could increase up to 1,330 individuals. Our results show that habitat improvement is necessary prior to the reintroduction of bullheads in the Sint‐Annabeek.     

Size‐dependent microhabitat use and intraspecific competition in Cottus gobio

An electrofishing survey of daytime shelter microhabitat use of bullhead Cottus gobio in a southern English chalk stream revealed positive selection for moderate water velocity, vegetation cover and coarse substrata. Water depth, other forms of cover, shade and substratum embeddedness had no significant influence on the distribution of fish. Microhabitat use was size‐dependent, with patches occupied by adult fish containing coarser substrata and less blanket weed ( Cladophora algae) than those occupied by smaller juvenile conspecifics. Differences in substratum use between size‐classes were less pronounced in parts of the stream shaded by the tree canopy. In laboratory tanks stocked at low fish density, both juveniles and adults favoured use of cobbles over pebbles. The response of fish to increased conspecific density was size‐dependent; juveniles reduced use of the coarse substratum whereas adults maintained their predominance in this habitat. An apparently greater shift by juveniles when in the presence of adults was significant at α = 0·10 only, as was an apparent reduction in interactions between size‐classes under low light intensity. The displacement of small juvenile fish from the preferred cobble substratum is consistent with the hypothesis that intraspecific competition contributes to the size‐related microhabitat shift observed in the field. Although there was a tendency for the strength of competition to be reduced at low light levels, the mechanism by which tree canopy cover affects microhabitat use remains uncertain.     

Investigating a major assumption of predictive instream habitat models: is water velocity preference of juvenile Atlantic salmon independent of discharge?

The mean column velocity preference of juvenile Atlantic salmon Salmo salar (LF 30–55 mm) was investigated by observing their spatial pattern of habitat use in a laboratory flume while varying discharge (Q) over a 18‐fold range (Q=2·6–46·8l s^‐1). Based on 341 fish observations at three discharges (Q=2·6, 15·0 and 46·8l s^‐1), three separate velocity preference curves were developed using standard procedures. The mean column velocities measured at 0·6 depth for the fish positions at the set low, medium and high discharges had medians of 7, 10 and 24 cm s^‐1, respectively, and varied significantly between the discharges. Across the range of flows, the fish utilized mean column velocities between 0 and 56 cm s^‐1, but the three velocity preference curves differed. Differences between juvenile Atlantic salmon use of habitat, defined according to mean column velocities at different discharges, were greatest at the lower end of the available range of velocities (<20 cm s^‐1). Weighted usable area (WUA), the output of the instream flow model PHABSIM that is used to describe the available habitat at a given discharge, was calculated for the flume using the preference curves built at the three set discharges. The model was highly sensitive to differences between the three preference curves and WUA varied by up to a two‐fold difference. Furthermore, habitat‐discharge relationships derived from the three preference curves were very different. Predicted habitat losses across the modelled range of discharges varied by up to 150% depending upon which velocity preference curve was used in the model. Thus, the assumption that a single preference curve can be applied across a range of discharges is not valid and is likely to result in large errors when employing PHABSIM and other models that use similar principles.     

Spatial microhabitat selection by Biomphalaria pfeifferi in a small perennial river in Tanzania

A study was carried out in the Mlali river in south-central Tanzania with two aims. First, to determine microhabitat availability in two sites (A and B) with respect to water depth, water velocity and dominant substratum type. Second, to assess microhabitat use by Biomphalaria pfeifferi, the intermediate host snail of intestinal schistosomiasis and to investigate whether these snails show preferences for certain microhabitats. The two sites differed significantly with respect to width, water depth, water velocity and substratum composition. It is suggested that the absence of B. pfeifferi from site B is mainly associated with the high water velocities at that site, where 62% of the measurements exceeded30 cm s^-1. In site A, the microhabitat use by 327 B. pfeifferi snails was assessed by means of direct observation. No significant relationships were found between snail size and the habitat variables investigated, indicating that snail size appeared to be of no importance in spatial microhabitat selection. B. pfeifferi snails showed statistically significant preferences for shallow water (depth: 2–7 cm) and the preferred water velocities ranged between 12 and 21 cm s^-1 with an estimated optimum at13.3 cm s^-1. No statistically significant preferences for substratum type were found. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mesohabitat use by bullhead (Cottus gobio)

Habitat composition and connectivity within a stream vary with changing flows but the influence of changing flow on habitat use by fish is not well understood. Meso- and microhabitat surveys were used to investigate habitat use by bullhead (Cottus gobio Linnaeus) in response to discharge variation in a small tributary of the Upper Severn, England. Mesohabitat mapping surveys were carried out over a range of summer flows (0.016–0.216 m³ s⁻¹) and were coupled with direct underwater observations (snorkelling) of fish location. Five mesohabitat types—glides, runs, riffles, chutes and pools—were present in the reach at all flows surveyed and ‘backwaters’ were found at three flows. The macro-morphology of the reach comprised six riffle–pool sequences divided into 27 mesohabitats with the maximum diversity (23 mesohabitats) at intermediate flows (Q ₄₃) and only 15 mesohabitats at Q ₉₅. Despite low numbers of fish (N = 78), bullhead displayed a strong association (51% of the fish) with glides—relatively deep habitats having high rates of velocity increase with flow. However, 54% of the fish were observed in two large, persistent mesohabitats, a glide (34%) and a pool (20%), both located below a faster flowing mesohabitat. Habitat use curves based upon micro-habitat data showed bullhead favoured low velocities (<0.30 m s⁻¹), depths less than 0.30 m and a cobble substratum. This study illustrates the value of cross-scale investigations in linking fish ecology, flow and physical habitat variability and suggests mesohabitat size, persistence and arrangement may influence fish distribution.     

Ontogenetic variation in density‐dependent growth of brown trout through habitat competition

1. Density‐dependent growth has been widely reported in freshwater fishes, but the ontogenetic evolution of competition and its subsequent effects on growth through a life span remains unclear. 2. Patterns of competition can be described by integrating population abundance data with habitat‐modelling results. Weighted usable area (WUA; m² WUA ha^?1) curves are obtained for each flow value and are then coupled with demographic data to obtain the occupancy rates (trout m^?2 WUA, the density of a given age class related to its suitable habitat) of the WUA for every age class, year and site. 3. We examined a long‐term data series searching for temporal variation in the influence of habitat occupancy rate on the growth of brown trout Salmo trutta. We tested whether (i) mean cohort mass (mean mass of the cohort during the first 3 years of life) is affected by the occupancy rate experienced across a life span; and (ii) the occupancy rate experienced at different ages influenced mean body size. 4. We observed a consistent negative power relationship between average cohort mass and mean occupancy rate through a life span, indicating that stronger cohorts were related to a reduced growth, with likely consequences for individual fitness. 5. The effects of occupancy rate on size‐at‐age were mainly detected in the size attained at the second year of life, but they were because of the competition at different times. Thus, the level of competition varied through ontogeny, in some of the rivers affecting growth since the first year of life, whereas in most of the rivers the main effects on body size resulted from the competition during the second year of life. 6. Occupancy rate appears more appropriate than density for assessing the occurrence of habitat competition in freshwater fishes, since it encompasses the differences in quantity and quality of suitable habitat for each age class. 7. Our study highlights the importance of density‐dependent growth as a key process in the dynamics of brown trout populations, its temporal variation depending on the temporal changes of density and the variation of competition associated with the habitat capacity for each life stage.     

Home range and habitat use of translocated endangered species,Cottus koreanus,in South Korea

The home range and characteristics of Cottus koreanus were investigated using passive integrated transponder (PIT) telemetry in the Gulji Stream, Korea, where the target species was artificially translocated. After release, tagged individuals moved up to 78?m away from the release site in search of proper habitats. The average distance moved until settlement was 17.1?m. The observed home range of settled individuals had longitudinal sections of 9.9?±?3.6?m and surface areas of 7.2?±?2.7?m². This is comparable to congeneric species that inhabit similar ecological habitats. Once individuals had settled, they rarely moved from that site except during the spring season. The typical microhabitat characteristics of the sites where the released individuals settled are: water depth of 5–10?cm, water velocity of 0.1–0.3?m?s^?1, and the size of boulders and cobbles of 10–20?cm in diameter. This study of translocated C. koreanus individuals provides detailed information about habitats that can be used for effective habitat restoration and successful translocations attempts of this species.     

A heterogeneous thermal environment enables remarkable behavioral thermoregulation in Uta stansburiana

Ectotherms can attain preferred body temperatures by selecting specific temperature microhabitats within a varied thermal environment. The side‐blotched lizard, Uta stansburiana may employ microhabitat selection to thermoregulate behaviorally. It is unknown to what degree habitat structural complexity provides thermal microhabitats for thermoregulation. Thermal microhabitat structure, lizard temperature, and substrate preference were simultaneously evaluated using thermal imaging. A broad range of microhabitat temperatures was available (mean range of 11°C within 1–2 m²) while mean lizard temperature was between 36°C and 38°C. Lizards selected sites that differed significantly from the mean environmental temperature, indicating behavioral thermoregulation, and maintained a temperature significantly above that of their perch (mean difference of 2.6°C). Uta's thermoregulatory potential within a complex thermal microhabitat structure suggests that a warming trend may prove advantageous, rather than detrimental for this population.     

Microhabitat use and preferences of the endangered Cottus gobio in the River Voer, Belgium

Microhabitat use and preferences of juvenile and adult bullhead Cottus gobio , from the River Voer, Flanders, were studied and compared across different seasons. Water depth, water velocity near the substratum, surface water velocity and substratum type used by C. gobio differed between seasons. These differences, however, were not attributable to differences in microhabitat availability. Adults appeared to prefer higher water velocities and coarser substrata than the average ones available in the basin. Although water depth appeared to have little influence on seasonal variation of microhabitat use in adult C. gobio , juveniles preferred deeper water and coarser substrata in winter, whereas in summer they appeared to use shallower water. There was a difference in microhabitat use between juvenile and adult bullhead only in summer.     

Effects of size structure and habitat complexity on predator–prey interactions

1. A predator's ability to suppress its prey depends on the level of interference among predators. While interference typically decreases with increasing habitat complexity, it often increases with increasing size differences among individuals. However, little is known about how variation in intrinsic factors such as population size structure alters predator–prey interactions and how this intrinsic variation interacts with extrinsic variation. 2. By experimentally varying the level of vegetation cover and the size structure of the predatory damselfly Ischnura posita Hagen, we examined the individual and interactive effects of variation in habitat complexity and predator size structure on prey mortality. 3. Copepod prey survival linearly increased as the I. posita size ratio decreased and differed by up to 31% among different predator size structures. Size classes had an additive effect on prey survival, most likely because intraspecific aggression appeared size‐independent and size classes differed in microhabitat preference: large I. posita spent 14% more time foraging on the floor than small larvae and spent more time in the vegetation with increasing habitat complexity. Despite this difference in microhabitat use among size classes, habitat structure did not influence predation rates or interference among size classes. 4. In general, results suggest that seasonal and spatial variation in the size structure of populations could drive some of the discrepancies in predator‐mediated prey suppression observed in nature, and this variation could exceed the effects of variation in habitat structure.     

Age,growth and habitat use of the topmouth gudgeon,Pseudorasbora parva in irrigation ditches on northwestern Kyushu Island,Japan

In Japan, Pseudorasbora parva has not been negatively affected by artificial changes in its habitat. Ecological traits of the species may explain this easy adaptation to artificial habitats. An ecological investigation of P. parva inhabiting irrigation ditches was conducted monthly for approximately two years on northwestern Kyushu Island, Japan. Measurements of 1927 individuals revealed two size classes, maturation age (1 year), and lifespan (1–2 years). Results of this study and previous studies show that the species exhibits life history plasticity. In addition, habitat use of ditches indicates that abundances correlated positively with water temperature and negatively with current velocity in the crop‐growing season, and positively with water depth and negatively with current velocity in the fallow season. Structural factors such as ditch revetment conditions and aquatic macrophyte cover were unimportant for this species. The study shows that the gudgeon adapts to artificial ditches easily and successfully because of both life history plasticity and wide‐scale use of the habitat.     

Ontogenetic shifts in habitat use by the endangered Roanoke logperch (Percina rex)

1. Conservation of the federally endangered Roanoke logperch (Percina rex, Jordan and Evermann) necessitates protection of habitat that is critical for all age classes. We examined habitat use patterns of individual logperch to determine: (1) if age classes of logperch in the Nottoway and Roanoke Rivers exhibit habitat selectivity, (2) if age classes differ in habitat use, and (3) if ontogenetic patterns of habitat use differ between the Roanoke and Nottoway river populations. 2. In the summers of 2000 and 2001, we observed 17 young‐of‐year (YOY) logperch [<4 cm total length (TL)], 13 subadult logperch (4–8 cm TL), and 49 adult logperch (>8 cm TL) in the upper Roanoke River, and 40 subadult and 39 adult logperch in the Nottoway River, Virginia. 3. All size classes of Roanoke logperch demonstrated habitat selectivity and logperch used a wide range of habitats in the Roanoke and Nottoway rivers during ontogeny. Habitat use by logperch varied among age classes and between rivers. 4. In the Roanoke River, adult and subadult logperch primarily preferred run and riffle habitat, often over gravel substrate. Subadults were found in lower water velocities and slightly more embedded microhabitats than adults. YOY logperch were found in shallow, stagnant backwaters and secondary channels. In the Nottoway River, both adult and subadult logperch were found over sand and gravel in deep, low‐velocity pools and runs. Subadults were observed in slightly more silted, lower velocity habitat than adults. Shifts in habitat use were more distinct between age classes in the Roanoke River than the Nottoway River. 5. Successful conservation of this species will involve sound understanding of spatial variation in habitat use over logperch life history and preservation of the ecological processes that preserve required habitat mosaics.     

Habitat degradation and trout stocking can reinforce the impact of flash floods on headwater specialist Alpine bullhead Cottus poecilopus – A case study from the Carpathian Mountains

In freshwater streams, flooding is a typical source of natural disturbance that plays a key role in the dynamics of animal populations and communities. However, habitat degradation and fish stocking might increase the severity of its impact. We tested the effects of a flash flood on the abundance of three size classes of headwater dwelling Alpine bullhead, Cottus poecilopus, in the streams of the Carpathian Mountains in the Czech Republic, that are stocked with hatchery‐reared brown trout, Salmo trutta. We showed that the overall abundance of Alpine bullhead was highest at the sites with the least degraded habitat (i.e., natural habitat) and we caught almost no Alpine bullhead at the sites with the most degraded habitat. The flash flood had a strong negative effect on the abundance of the largest individuals of Alpine bullhead. Abundance of small and medium size Alpine bullhead was negatively affected by the abundance of adult stocked brown trout before as well as after the flash flood. However, negative effect of adult brown trout abundance on abundance of large Alpine bullhead was not significant before the flash flood, and it became significant after the flash flood. This could indicate an accumulation of negative impacts of trout stocking and flash flood on this size class. Overall, our results suggest that stocking of hatchery trout and habitat degradation can reinforce the impact of flash floods on the population of Alpine bullhead in the streams of the Carpathian Mountains.     

Effect of physical factors on the distribution of filamentous green algae in the Tama River

 The distribution of stream-specific filamentous green algae (SSFG) was investigated in the middle reach of the Tama River, Japan. Cladophora glomerata (L.) Kützing and Stigeoclonium sp. dominated among five taxa of SSFG collected in the riverbed with fast currents. These two species were abundant in shallow (<20 cm) riffles with high current velocity (>30 cm s⁻¹), a habitat characterized by high light intensity and extensive aeration. SSFG biomass fluctuated greatly (range, 1.2–85.3 cm² m⁻²), exhibiting no clear seasonal trend. The tufts of SSFG grown on riffle cobbles decreased rapidly when these cobbles were transferred to habitats with either deep water, low current velocity, or both. Laboratory experiments revealed that aeration retarded the decrease in SSFG in incubation vessels. These results suggest that the turbulent conditions of riffle habitats are important for the growth and survival of SSFG in the Tama River. Received: September 5, 2001 / Accepted: April 25, 2002     

Summer daytime habitat and population density of the torrent catfish, Liobagrus reini, in the Urano River

The population density and summer daytime habitat characteristics of the endangered torrent catfish, Liobagrus reini, in the Urano River, a tributary of the Chikuma River in Nagano, central Japan, were investigated. A total of 105 individuals were captured in 2001–2003, and the estimated population density 100m^–2 in the whole study area ranged from 0.20 to 2.96. Liobagrus reini were captured from under cobbles and boulders, interstices in bedrock, and in clumps of roots of terrestrial vegetation along banks. Compared with the distribution of physical factors in the study area, the fish selected shallow habitats with the riverbed covered by cobbles and boulders. Boulders and larger cobbles were chosen by larger individuals as a habitat. Habitat selection was not correlated with current velocity, and some individuals were sampled near (<1m) the riverbank with no current. For the conservation of L. reini, the preservation of natural riverbanks and areas with boulders and large cobbles in the riverbed is concluded to be important.     

Characterization of benthic microhabitat: An experimental system for aquatic insects

An experimental system used to determine microhabitat current velocity and microhabitat selection by aquatic insects is described. The experimental system includes a microvelocity probe and a hydraulically calibrated artificial substrate. A thermistor velocity probe detects flow velocities to 0.5 m s^–1 near the surface of substrates at locations inhabited by aquatic insects. The artificial substrate was designed to provide two major habitat types, highly turbulent vortex areas and regions with unidirectional, near laminar flow. Substrate calibration and microhabitat characteristics of the substrates are demonstrated. Experimental studies of Simulium sp. location on substrates indicated that while simuliid larvae are characteristic of lotic, erosional habitats, actual microhabitats selected are governed by substantially lower flow velocity.     

Habitat use and diet of two stream gobies of the genus Rhinogobius in south-western Shikoku,Japan

The importance of interspecific competition to habitat use by two congeneric stream gobies, Rhinogobius sp. LD (large-dark type) and CB (cross-band type), was studied by: (i) examining differences in habitat use by each species along the course of the stream; and (ii) comparing microhabitat use and the diet of each species between in allopatry and in sympatry in tributaries of the Shimanto River, south-western Shikoku, Japan. Rhinogobius sp. LD mainly used riffles through the course of the stream. Although CB also mainly used riffles in the lower reaches where CB was numerically dominant, the greater use of riffles by CB was not observed in upper reaches where LD was dominant. Microhabitat analysis revealed that both LD and CB preferred lower bottom velocity in faster current in both allopatry and sympatry. In sympatry, however, LD used coarser substrate and faster current than CB, and both LD and CB used narrower ranges of microhabitat conditions than in allopatry. Dietary analysis indicated that both allopatric and sympatric LD preferred baetids, which are apt to drift, suggesting they adopted ambush foraging. Allopatric CB preferred leptophlebiids and chironomids, which are also apt to drift, whereas sympatric CB did not prefer such invertebrates. Overall results of this study suggest that LD and CB compete for better feeding habitats, CB shift their habitat use and foraging mode under the influence of LD, and current velocity and substrate coarseness are key factors in their habitat segregation.

     

An ‘ecological trap’ for yellow warbler nest microhabitat selection

Contrary to assumptions of habitat selection theory, field studies frequently detect ‘ecological traps’, where animals prefer habitats conferring lower fitness than available alternatives. Evidence for traps includes cases where birds prefer breeding habitats associated with relatively high nest predation rates despite the importance of nest survival to avian fitness. Because birds select breeding habitat at multiple spatial scales, the processes underlying traps for birds are likely scale‐dependent. We studied a potential ecological trap for a population of yellow warblers Dendroica petechia while paying specific attention to spatial scale. We quantified nest microhabitat preference by comparing nest‐ versus random‐site microhabitat structure and related preferred microhabitat features with nest survival. Over a nine‐year study period and three study sites, we found a consistently negative relationship between preferred microhabitat patches and nest survival rates. Data from experimental nests described a similar relationship, corroborating the apparent positive relationship between preferred microhabitat and nest predation. As do other songbirds, yellow warblers select breeding habitat in at least two steps at two spatial scales; (1) they select territories at a coarser spatial scale and (2) nest microhabitats at a finer scale from within individual territories. By comparing nest versus random sites within territories, we showed that maladaptive nest microhabitat preferences arose during within‐territory nest site selection (step 2). Furthermore, nest predation rates varied at a fine enough scale to provide individual yellow warblers with lower‐predation alternatives to preferred microhabitats. Given these results, tradeoffs between nest survival and other fitness components are unlikely since fitness components other than nest survival are probably more relevant to territory‐scale habitat selection. Instead, exchanges of individuals among populations facing different predation regimes, the recent proliferation of the parasitic brown‐headed cowbird Molothrus ater, and/or anthropogenic changes to riparian vegetation structure are more likely explanations.     

Effects of habitat transitions on rainforest bird communities across an anthropogenic landscape mosaic

We compared bird community responses to the habitat transitions of rainforest‐to‐pasture conversion, consequent habitat fragmentation, and post‐agricultural regeneration, across a landscape mosaic of about 600 km² in the eastern Australian subtropics. Birds were surveyed in seven habitats: continuous mature rainforest; two size classes of mature rainforest fragment (4–21 ha and 1–3 ha); regrowth forest patches dominated by a non‐native tree (2–20 ha, 30–50 years old); two types of isolated mature trees in pasture; and treeless pasture, with six sites per habitat. We compared the avifauna among habitats and among sites, at the levels of species, functional guilds, and community‐wide. Community‐wide species richness and abundance of birds in pasture sites were about one‐fifth and one‐third, respectively, of their values in mature rainforest (irrespective of patch size). Many measured attributes changed progressively across a gradient of increased habitat simplification. Rainforest specialists became less common and less diverse with decreased habitat patch size and vegetation maturity. However, even rainforest fragments of 1–3 ha supported about half of these species. Forest generalist species were largely insensitive to patch size and successional stage. Few species reached their greatest abundance in either small rainforest fragments or regrowth. All pastures were dominated by bird species whose typical native habitats were grassland, wetland, and open eucalypt forest, while pasture trees modestly enhanced local bird communities. Overall, even small scattered patches of mature and regrowth forest contributed substantial bird diversity to local landscapes. Therefore, maximizing the aggregate rainforest area is a useful regional conservation strategy.     

Determinants of preferred intertidal feeding habitat for Eastern Curlew: A study at two spatial scales

Abstract Broadscale habitat use by Eastern Curlews (Numenius madagascariensis) in their non‐breeding range in eastern Australia was assessed using low tide surveys on feeding grounds, where 60 skilled volunteers made repeated counts of the birds on intertidal flats, across 41% (9500 ha) of the intertidal habitat within Moreton Bay, Australia. We analysed 32 defined sections of intertidal flat, of roughly equal area (mostly 200–400 ha), which varied greatly in their curlew density (2–47 birds per 100 ha) and also in substrate and other environmental features. Sites with the least resistant substrates had densities three times those with the most resistant substrates. Of 10 environmental characteristics measured for each site, substrate resistance was the best predictor of curlew density (r² = 0.45). Characteristics that were poor predictors included distance to the nearest roost, level of human disturbance and distance to urban settlement. For a finer‐scale assessment, microhabitat use and feeding behaviour were recorded during low tide within 12 intertidal flats, which varied in size (23–97 ha), substrate, topography and other features. Across all flats, curlews strongly preferred to feed relatively close (0–50 m) to the low‐water line. They fed on a variety of substrates (including sand, sandy‐mud, mud and seagrass) in broadly similar proportions to their occurrence in the habitat. There was a statistically significant preference for sand, although its magnitude was not strong. These results indicate that curlews select habitat most strongly at a between‐flat rather than within‐flat scale.