Seasonal change in Red-backed Shrike Lanius collurio territory quality - the role of nest predation

This paper examines the relationships between territory preference, reproductive performance and nest predation in a Red-backed Shrike Lanius collurio population breeding in rapidly changing farmland. Territory preference was measured by (a) the order of laying dates in territories within years and (b) territory occupation frequency over a five-year period. Seven environmental variables were tested but only the density of Sloe (Blackthorn) Prunus spinosa in territories was correlated positively with territory occupation frequency. Within years, Red-backed Shrikes started to breed earlier in territories with more Sloe, but reproductive performance was not related consistently to territory differences. A high proportion of Sloe-rich territories was vacant each year. Thus, the observed negative association between settlement order and amount of Sloe may reflect a seasonal change in habitat preference. Early breeders prefer Sloe-rich territories whereas late birds prefer Sloe-poor territories. Supporting evidence is that the proportion of occupied territories that was Sloe-rich was higher for early than for average or late first breeding attempts. Moreover, in contrast to early in the season, the probability of a replacement clutch following nest failure was not associated with the amount of Sloe, but increased with increasing densities of Juniper Juniperus communis. Late in the nesting season, pairs breeding in Sloe-rich territories suffered higher nest predation than those breeding in Sloe-poor territories. In early nesting attempts, however, the relationship was reversed. Nest predation is probably an important selective agent on habitat selection since it was the principal factor explaining variation in the numbers of fledglings produced among territories. Thus, the Red-backed Shrike may shift territorial preferences adaptively as the season progresses to match within-season changes in predation pressure in different types of territories.     

Between land abandonment and agricultural intensification: habitat preferences of Red-backed Shrikes Lanius collurio in low-intensity farming conditions

Capsule The conservation of Red-backed Shrikes on farmland habitats depends on extensive farming conditions.

Aims To evaluate breeding density and habitat preferences of the declining Red-backed Shrike and relate its occurrence to an environmental gradient ranging from land abandonment to intensive farming.

Methods The study was carried out in the Apennines (northern Italy), at nine 21-ha study plots. We identified factors affecting breeding density and habitat preferences at two spatial scales (landscape and territory) and analysed the variation in territory density according to the relative farming intensity in a low-intensity agricultural landscape.

Results The presence of shrubs and cultivated/grazed land positively influenced the number of Red-backed Shrike territories per plot, while the species' settlement within plots was related to higher values of shrub cover and the presence of hedges. Shrike occurrence was associated with land-use categories intermediate between land abandonment and intensive agriculture.

Conclusions This study provides a first detailed assessment of Red-backed Shrike habitat requirements in southern Europe. Favoured habitats were pasture/cultivation mosaics flanked by or interspersed with shrubs/hedges (15–20% of the surface of the 1-ha medium-sized territory). Thus, the conservation of Red-backed Shrikes in low-intensity southern European farmland appears to reflect a trade-off between agricultural intensification and long-term land abandonment.     

Caterpillar abundance in the territory affects the breeding performance of great tit Parus major minor

The effects of caterpillar food supply on the breeding performance of a population of the Japanese great tit Parus major minor were investigated. Since more than 90% of the food items in our study site were caterpillars living on trees, we estimated the food availability using 20 frass traps per hectare. The sampling error of this method was about 10% on average, which was accurate enough to detect differences between territories. Food abundance at laying in each territory affected the timing of egg laying. However, food amount after hatching was correlated with clutch size. No relationship was found between fledgling quality and food availability, probably because the effects of local variation in food abundance could be canceled out by parental effort such as extending the foraging area. There was a significant negative correlation between the length of the nestling period and food availability. We suggest that parent tits decide the timing of fledging at the point where two factors, predation risk before fledging and additional improvement of nestling quality, are balanced. Food availability just after fledging affected the length of post-fledging parental care; it seems that fledglings in “poor” territories would have had difficulty in finding food and hence needed to depend on their parents longer than those in “rich” territories. Received: 10 June 1997 / Accepted: 29 December 1997     

Determinants of territory size in the pomacentrid reef fish,Parma victoriae

Summary Factors governing the size of territories defended by the pomacentrid reef fish, Parma victoriae, were investigated, prompted by contradictory predictions in the literature concerning the effects of food supply and competitors. Observations were carried out over the non-breeding period (March–October) on a medium density population in which territories were partially contiguous. The territory size of adult fish varied between 3 and 26 m², and was inversely correlated with local densities of conspecifics. The same range in territory size was found for both males and females, which did not differ in the time they spent on territory defence and foraging activities. No correlation existed between territory size and the abundance of algal food, body size, age or time spent on territory defence. Also, there was little variation in territory size over time, despite seasonal changes in the abundance of food algae.Experimental reduction of food supplies on isolated territories of males and females had no effect on territory size. In a higher density habitat an experiment was carried out in which population density and food abundance were simultaneously manipulated. This showed that territory size was primarily determined by intraspecific interactions, as territories exhibited considerable increases in size upon removal of neighbours. No changes in the size of defended areas resulted from either artificial increases or decreases of food levels. There were also no changes in the time spent on defence of territories, foraging time or feeding rates associated with food manipulations or territory expansion, which suggested that food was not a limited resource. This conflicted with current theories proposed to explain territory defence and expansion. It is hypothesized that intraspecific interactions constrain territory size well below the optimum in terms of the abundance of preferred food algal species.     

The role of natural habitats in agricultural systems for bird conservation: the case of the threatened Lesser Grey Shrike

Birds of agricultural systems are one of the most threatened groups of birds in Europe mainly due to their sharp population decline in recent decades. Habitat intensification resulting from more productive agricultural practices has been proposed as a major cause for these declines. However, especially in some regions such as Eastern European and Mediterranean countries, little is known about the ultimate factors linked to habitat intensification that drive population declines for different species. The Lesser Grey Shrike is a good study species for a better understanding of such processes since it is closely related to agricultural habitats in Europe and has suffered a strong decline in range and population size across the western half of the continent. In this study, we explored variations in breeding parameters of this shrike related to habitat composition and food supply at the territory level. We found that fledgling success of early breeders was related to the presence of natural (shrub lands) and semi-natural (fallows) habitats in the predominantly agricultural matrix that dominated breeding territories. Their influence on fledgling success appeared to be mediated by a higher arthropod availability on these habitats. Indeed, Lesser Grey Shrike showed a strong preference for these habitats as hunting locations. Our results highlight the importance of natural habitats in intensified agricultural land mosaics for the conservation of bird species. We suggest that management plans should pay special attention to the availability of habitats which serve as high quality food reservoirs and can potentially contribute to enhance the species population viability in an area. Finally, we discuss the possible link between agricultural intensification and Lesser Grey Shrike population declines in Western Europe.     

The influence of food abundance,food dispersion and habitat structure on territory selection and size of an Afrotropical terrestrial insectivore

Most tropical insectivorous birds, unlike their temperate counterparts, hold and defend a feeding and breeding territory year-around. However, our understanding of ecological factors influencing territory selection and size in tropical insectivores is limited. Here we examine three prominent hypotheses relating food abundance, food dispersion (spatial arrangement of food items), and habitat structure to territoriality in the Usambara Thrush Turdus roehli. We first compared leaf-litter macro-invertebrate abundance and dispersion, and habitat structure between territories and random sites. We then examined the relation between these same ecological factors and territory size. Invertebrate abundance and dispersion were sparsely and evenly distributed across our study system and did not vary between territories and random sites. In contrast, habitat structure did vary between territories and random sites indicating the Usambara Thrush selects territories with open understorey and closed overstorey habitat. Invertebrate abundance and dispersion within territories of the Usambara Thrush were not associated with habitat structure. We believe the most likely explanation for the Usambara Thrush’s preference for open understorey and closed overstorey habitat relates to foraging behavior. Using information-theoretic model selection we found that invertebrate abundance was the highest-ranked predictor of territory size and was inversely related, consistent with food value theory of territoriality.     

Habitat selection and reproductive success of Ortolan Buntings Emberiza hortulana on farmland in central Sweden – the importance of habitat heterogeneity

Many granivorous birds have shown severe population declines in Europe during recent decades. The aim of the present study was to analyse habitat preferences and reproductive success of one such species, the Ortolan Bunting Emberiza hortulana, in different farmland habitats in south‐central Sweden. Four seemingly different land‐use types were preferred: permanent set‐asides, short rotation coppice, and grazed and unmanaged semi‐natural pastures. Territories and random sites differed considerably in the proportion of these preferred land‐use types; 39% of territories had > 70% preferred habitat (at the 100‐m scale) compared to 5% of random sites. In contrast, 22% of territories and 65% of random sites had no preferred habitats. All the preferred habitats had heterogeneous ground vegetation characterized by patches with bare ground, or at least sparse ground vegetation, intermixed with patches with taller vegetation. Ortolan Buntings also preferred a heterogeneous habitat structure with occurrence of field islets, shrubby edges, barns and electric wires, which could act as song posts or suitable nest‐sites, in 88% of territories. At a larger (1‐km square) scale, territories occupied by pairs aggregated strongly in areas with high proportions of preferred habitats. The number of territories with single males correlated positively with the number of pairs, which suggests that conspecific attraction may influence territory distribution. No measured habitat factors were related to reproductive success. However, due to habitat preferences and the higher proportion of paired males in one habitat type (set‐aside), the production of young (fledglings/ha) is expected to be higher in set‐asides, as well as in short‐rotation coppices and semi‐natural pastures. Thus, these habitats are important for the conservation of the Ortolan Bunting. Large areas with habitat structures such as field islets are especially important because the Ortolan Bunting breeds in aggregations in these areas.     

Foraging behaviour and diet in two sympatric shrike species during autumn migration across the Arabian Peninsula

In situations of restricted food supply, the trophic niches of closely-related species of animals should be separate. For sit-and-wait hunters, such as shrikes, this is associated with competition for food and hunting sites. In the present study, the foraging behaviour of two shrike species – Red-tailed Shrike Lanius phoenicuroides and Red-backed Shrike Lanius collurio – was studied in a desert habitat in Oman. The fieldwork was carried out in September 2019, during the peak migration of these birds. Their behaviour was recorded in detail during 30-minute observation bouts. A General Linear Mixed Model with logit link function and binomial error variance was used to compare their behaviour. The type of perch and its height did not differ between them, but there were significant differences in their use of look-out posts only in the mean duration of a single perching event, which was more than twice as long in Red-backed Shrike. No differences in prey size were found between the species and hunting success (the ratio of successful attacks to all attacks) was similar in both (RtS-RbS: 46 vs. 61%). Dietary diversity was twice as great in Red-tailed Shrike as in Red-backed Shrike, but in general, their diets did not differ very much. Dietary overlap between the species at this level of prey identification was 92%. This absence of differences in some aspects of behaviour and diet may be due to the similarity of the two species, above all their same body size, and even the possibility of hybridization. If the species compared are so similar due to body size, behaviour and evolutionary relationship their food niches may overlap.     

Selection of breeding territory by little bustard (<Emphasis Type="Italic">Tetrax tetrax</Emphasis>) males in Central Spain: the role of arthropod availability

The influence of arthropod availability on the formation of male little bustard breeding territories in central Spain was studied in two consecutive years. Arthropods (68,217 individuals) were sampled using pitfall trapping and male territories estimated by means of kernel functions. Hymenopterans (ants), beetles, mites and spiders were the main taxa found in the samples, while the highest contributions in terms of biomass came from hymenopterans, beetles and orthopterans. The only group that exhibited significant biomass differences between territory and non-territory locations was that of the beetles; this pattern was consistent between years. Carabidae was the main beetle family in terms of biomass, followed by other large beetles such as Tenebrionidae, Cleridae, Scarabeidae and Elateridae. The biomass of Carabidae that were larger than 15 mm was significantly higher within territories than outside them. The biomass of Cleridae was greater in fallows, while Elateridae were more abundant in arable fields. The total biomass of beetles that were larger than 15 mm was higher in arable fields than in fallows. Family richness differed between years, while diversity showed differences between agricultural fields (it was highest in fallows), although these variables did not differ between territory and non-territory locations. Results indicate that large beetles (particularly carabids) seem to be a valuable food resource that is defended by little bustard males during the highly energy-demanding breeding season, which is discussed here in relation to habitat selection, the mating system and its implications for the conservation of the species.     

Determining habitat quality for the cooperatively breeding Rufous Treecreeper,Climacteris rufa

Abstract The theory of habitat selection predicts that organisms should use habitat that maximizes their fitness. The cooperatively breeding Rufous Treecreeper, Climacteris rufa, exhibits non‐random habitat use at a number of spatial scales. By assessing correlative relationships between nest‐site use and nest success, and territory use and reproductive success and survival, it was determined whether non‐random use of habitat yields fitness benefits. It was also determined whether breeding group size contributed significantly to fitness once differences in territory quality had been considered. Structural characteristics of nest sites that were positively correlated with the probability of a site being used had no relationship with nest success. This result probably reflects the relatively unrestricted access to an abundance of suitable nest sites in the study area. Habitat traits that predicted territory use by treecreepers were positively correlated with a number of fitness measures. They were also positively correlated with breeding group size and provisioning rate to nestlings, which in turn were correlated with fitness. However, group size was not significantly related to any measure of fitness, except primary male survival, once territory quality had been considered. The quality of territories occupied by Rufous Treecreepers appeared to be a significant factor for breeding group fitness.     

Effects of variation in breeding habitat on Ring Ouzel Turdus torquatus productivity and chick condition

Capsule Territory habitat influenced clutch size and within-brood variability of chick condition in Ring Ouzel Turdus torquatus.

Aims To assess the relationship of Ring Ouzel productivity and chick condition with territory habitat, in order to improve understanding of the importance of breeding habitat for population change.

Methods Productivity and chick condition were recorded for Ring Ouzel pairs in a small area of upland Scotland and these were related to vegetation and physical characteristics for all breeding territories using General Linear Models.

Results We found that clutch size and variability of chick condition varied with Ring Ouzel breeding habitat.

Clutch size was related to variation in territory habitat, broadly increasing with territory grass, sedge and rush cover. The best-supported models for within-brood variability of chick condition included fledgling number and territory habitat, with chick condition broadly becoming more variable with territory bracken cover. Relationships between breeding habitat and brood size, fledgling number or mean chick condition were not supported by the data, although statistical power was low.

Conclusion Breeding habitat may be a driver of demographic rates of Ring Ouzel, with the effects of poor habitat being passed on indirectly through chick condition. The population-level importance of these effects is unclear, but this study highlights a possible link between recent observed habitat changes and first-year survival, the demographic parameter contributing most to variation in population growth rate in UK Ring Ouzels.     

Evaluating Habitat Quality for the Dusky Flycatcher

Abstract: We studied the dusky flycatcher (Empidonax oberholseri) at 8 sites in central Idaho, USA, in 2002 and 2003 to examine relationships among vegetation cover, density of breeding conspecifics, and indicators of habitat quality. Number of breeding territories and number of fledglings per hectare were positively associated, suggesting that the dusky flycatcher experienced increased reproductive success where it bred at the highest densities. However, the relationships between nesting success, annual reproductive success, number of fledglings per hectare, and amount of understory cover showed substantial annual variation. Nesting success did not differ significantly across sites or between years. Both reproductive success, expressed as young produced per hectare (range: 0.34–3.09 in 2002 and 0.79–3.82 in 2003) and young produced per nesting attempt (range: 0.71–2.78 in 2002 and 1.11–3.10 in 2003), differed across study sites in each year. Mean clutch size did not differ significantly among sites or years. Mean egg weight showed significant variation across some sites within years and was associated negatively with the 3 measures of reproductive success in 2002, although small sample sizes prevented reliable inference about the appropriateness of this measure as an indicator of habitat quality. Mean clutch size and mean egg weight were not associated with vegetation cover variables. Thus, dusky flycatcher reproductive success showed inconsistencies with individual vegetation measurements at the site scale. Forest managers who use vegetation treatments to increase amounts of understory shrub cover (e.g., by removing portions of the overstory conifer canopy) should increase densities of this species and, in turn, increase number of fledglings produced, but these responses appear to be better measured at the territory or nest scales than at the stand or site scales.     

Storing prey in larders affects nestling haematological condition in the Red-backed Shrike (Lanius collurio)

Many animals, including shrikes (Laniidae), are known to store food. This behaviour ensures food availability during inclement weather, for rearing nestlings or signalling territory quality. Unlike most other shrike species, which accumulate food before breeding, Red-backed Shrikes Lanius collurio store food in larders, mainly during the nestling and fledgling periods. If this is an adaptive behaviour, variation in this behaviour should affect either or both the number and condition of nestlings, which may benefit from such larders. We assessed the haematological condition of Red-backed Shrike nestlings in east-central Poland in 2021 using a suite of blood parameters relating to sites where shrikes did or did not store food. Haemoglobin concentrations were positively correlated with larders, being significantly higher in nestlings of pairs that stored prey compared with those whose parents did not do so. White blood cell counts were lower in nestlings whose parents kept larders. Red blood cell counts and glucose concentrations in nestlings were not related to whether parents had larders. Food storage probably ensures a more constant access to food, which results in a superior haematological condition in nestlings.     

Habitat preferences of Red-backed Shrikes Lanius collurio and Barred Warblers Sylvia nisoria breeding sympatrically in a wetland/farmland mosaic

Capsule: The Red-backed Shrike Lanius collurio and the Barred Warbler Sylvia nisoria had similar habitat preferences and their territories often overlapped. However, we found that Red-backed Shrikes were more flexible in habitat choice whilst Barred Warblers had more specific requirements.

Aim: We aimed to analyse and compare distribution and habitat preferences of Red-backed Shrikes and Barred Warblers breeding sympatrically in semi-natural landscape in a wetland/farmland mosaic.

Methods: We examined habitat availability and use by the two species within their breeding territories to identify differences in habitat selection.

Results: Territories of both species were similar in habitat composition and used levees, bushes, fallow areas and single trees. However, the spatial characteristics of the territories differed between species. Red-backed Shrikes used a wider range of sizes and shapes of habitat patches, whilst Barred Warblers preferred a more complex landscape structure and a higher diversity of habitat types. We also found that areas of 71% of Barred Warbler and 34% of Red-backed Shrike territories overlapped.

Conclusion: Whilst both species showed similar habitat choices, they appeared to differ significantly in terms of landscape structure: Red-backed Shrikes were more flexible and less selective than Barred Warblers in their habitat choice.     

Territory quality determines social group composition in Ethiopian wolves Canis simensis

1. We contrast the value of four different models to predict variation in territory size as follows: resource density (the ideal free distribution), population density, group size and intruder pressure (relative resource-holding potential). In the framework of the resource dispersion hypothesis, we test the effect of resource abundance and spatial variation in resource distribution on the age/sex composition of social groups. 2. We explore these drivers of territory size and group size/composition in Ethiopian wolves Canis simensis in the Bale Mountains, Ethiopia, using fine-scale distribution maps of their major prey species based on satellite-derived vegetation maps. 3. The number of adult males is correlated with territory size, while prey density, wolf population density and intruder pressure are not associated with territory size. On average, each additional adult male increases territory size by 1.18 km(2). 4. Prey abundance increases with territory size (average biomass accumulation of 6.5 kg km(-2)), and larger territories provide greater per capita access to prime foraging habitat and prey. 5. The age/sex composition of wolf packs is more closely related to territory quality than territory size. Subordinate adult females are more likely to be present in territories with greater proportions of prime giant molerat Tachyoryctes macrocephalus habitat (i.e. >80% of Web Valley territories and >20% in Sanetti/Morebawa), and more yearlings (aged 12-23 months) occur in territories with greater overall prey biomass. 6. Wolf packs with restricted access to good foraging habitat tend to defend more exclusive territories, having a lower degree of overlap with neighbouring packs. 7. The greater per capita access to prey in large groups suggests a strong evolutionary advantage of collaborative territorial defence in this species, although the relative costs of territorial expansion vs. exclusion depend upon the spatial distribution of resources. We propose a model whereby territory size is determined by the number of adult males, with the presence of subordinate females and yearlings dependent on the quality of habitat, and the abundance and distribution of prey, incorporated within territory boundaries.     

Patterns of territory size and defence level in rural and urban tawny owl (Strix aluco) populations

The effect of different variables on the territory size and defence level of tawny owl ( Strix aluco L.) populations was studied in two habitats: mixed farmland (1976–1978) and town (1986–1988). Territory size was determined by plotting the position of territorial challenges (hoots) of males which were individually recognizable in most cases. No differences were found in size, defence, number of competitors and biomass between territories in farmland and in town, but territories in town were more fragmented and showed a larger nearest neighbour distance. Size of rural territories was adequately predicted both by some structural habitat features and food supplies, while size of urban territories was affected only by habitat structure and by years of territory occupancy. No effect on territory size by competing neighbours was found in either habitat, thus confirming that behavioural interactions between the owners of territories and potential settlers prevent a decrease of territory size.
Defence level of urban territories was affected by 'social'variables (nearest neighbour distance and years of occupancy), structural variables (percentage of poplar grove and diversity), and food supply, while in rural territories only structural variables (fragmentation or natural vegetation) and food supplies affected defence level.
This was due to different settlement tactics in the two areas, depending on the extent and quality of suitable habitat.     

The effect of food abundance on territory size and population density of juvenile steelhead trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

Optimal territory size models predict a decrease in territory size with increasing food abundance. However, most of these models may not be applicable to juvenile salmonids in streams, because they defend contiguous territories at high densities. The optimal size of a contiguous territory is predicted to (1) be independent of food abundance when food is rare and (2) decrease only when food abundance is high enough to induce a reduction in territory size below the contiguous optimum. To test these predictions, we raised equal densities of juvenile steelhead trout in outdoor stream channels over a 32-fold range of food abundance in the absence of emigration for 25 days. Increasing competition for scarce food resulted in increasing mortality, higher willingness to emigrate, higher variance in body mass, lower growth, lower population density and lower biomass. The size of territories decreased with increasing local population density, and increased with increasing body size. However, territory size did not change with food abundance, a result consistent with the prediction of a contiguous territory size model. On average, total salmonid biomass increased 5.7 times in response to the 32-fold increase in food abundance. Our data provide strong support for an earlier quantitative relationship between the abundance of stream salmonids and their food.     

Interactive effects of food and age on breeding in the Montagu's Harrier Circus pygargus

We evaluated the direct and interactive effects of food and age on reproduction in the Montagu's Harrier Circus pygargus , to test whether variation in food supply was likely to affect age-specific breeding probability or success. Younger females were more frequently non-breeders than older females. When breeding, older females laid earlier, produced larger clutches, failed less often and had higher number of fledglings than younger females. Probability of breeding was higher, laying was earlier, and clutch size and number of fledglings per pair increased with increasing food abundance. A significant interaction between food and age was observed in both breeding probability and breeding performance: older females were more likely to breed than younger females when food abundance was low, and younger females performed less well in good food conditions than older females. Overall, differences between age groups were most marked in extreme food conditions, regardless of the quality of the conditions.     

Spring movements of Rüppell's Vulture Gyps rueppellii across the Strait of Gibraltar

Most of our understanding of territorial behaviour in birds comes from studies of temperate species. Territoriality and factors influencing territory size of tropical birds are still poorly studied. In this study, 11 territories of the Cinnamon-breasted Rock Bunting Emberiza tahapisi were measured in the Amurum Forest Reserve and adjoining farmlands. Factors influencing the habitat choice of this species were also studied. Territory sizes ranged from 0.1–0.3 ha with a mean territory size of 0.19 ± 0.1ha. Territory size decreased with increasing food abundance and increased with tree height and number of saplings. The birds did not show signs of territoriality in farmlands but flocked in small groups (mean group size 6.88 ± 0.89). Flock size also increased with increasing number of seeds. In the forested land, birds showed a preference for rocky outcrops, whereas in farmlands, they appeared to prefer open and newly cultivated farmlands with little or no ground cover. Understanding the influence of habitat variables on territory size and habitat selection in a locally abundant and widely distributed tropical species such as the Cinnamon-breasted Rock Bunting thus offers unique opportunities for understanding how changes in landscape caused by land-use regimes may affect populations.     

Effects of local and landscape-scale habitat variables on abundance and reproductive success of wetland birds

Both local and landscape-scale habitat variables influence the abundance of wetland breeding birds. Few studies, however, simultaneously assess the effects of habitat variables at multiple spatial scales or consider effects on reproductive success. Therefore, we examined the effects of wetland and landscape-scale habitat variables on the abundance of nine breeding bird species and the effects of nest, wetland, or landscape-scale habitat variables on the nest success, clutch size, or number of fledglings of four species at 15 cattail (Typha sp.)-dominated wetlands in an agricultural region around Peterborough, Ontario, Canada. The abundance of Least Bittern (Ixobrychus exilis), Common Moorhen (Gallinula chloropus), and Marsh Wren (Cistothorus palustris) increased as wetland water depth increased; the abundance of Common Moorhen and Marsh Wren increased as wetland size increased; and the abundance of Marsh Wren increased as the amount of wetland in the surrounding landscape increased. Red-winged Blackbird (Agelaius phoeniceus) nest success decreased as nest cover increased. Clutch sizes were uninfluenced by the habitat variables that we considered. The number of Red-winged Blackbird fledglings per successful nest increased as wetland size increased and as the amount of wetland in the surrounding landscape increased. We speculate that food limitation in small wetlands may be responsible for the pattern in Red-winged Blackbird fledging success. The abundance and nest success of Virginia Rail (Rallus limicola) and Sora (Porzana carolina) were uninfluenced by the habitat variables we considered. Future research should consider mate attraction and productivity in relation to local and landscape-scale habitat variables for these and other secretive species. Our study suggests that wetland conservation will be most effective if it considers habitat variables at multiple spatial scales.