Total Number Of Bird Species Research Articles

First record of African Dusky Flycatcher on Robben Island

An African Dusky Flycatcher Muscicapa adusta was observed on 23 May 2024 on Robben Island, Table Bay, South Africa. This brings the total number of bird species recorded on Robben Island to 166; the number reported since 2000 is 135.

Biodiversity of ornifauna on the territory of the Chograisky Reserve

The article is devoted to the biodiversity of the ornifauna on the territory of the Chograisky Reserve. It is noted that the reserve is a center of attraction for a large number of waterfowl and, first of all, rare and endangered birds. It is shown that the reserve is geographically isolated and birds tend to water bodies located on the paths of seasonal bird migrations. Information on the biodiversity of bird species is presented. Of the vertebrates found in the Reserve, birds are the most representative in terms of species composition. The total number of bird species registered here is about 90 species. Taking into account biotic links of birds with water bodies, such groups as waterfowl, near-water birds and occasional birds were identified. Depending on the nature of nesting, method of feeding and degree of attachment to a water body in the development cycle, the largest number of species are surface waterfowl and diving species. birds are indicators of environmental conditions. High indicators of species diversity indicate stability and favorability of bird habitat factors on the territory of the Reserve. At present, a fairly stable system of bird communities has been formed in the area.

Acoustic indices estimate breeding bird species richness with daily and seasonally variable effectiveness in lowland temperate Białowieża forest

Acoustic indices have been proposed as rapid and easy to apply tool for biodiversity estimation of vocalising animals without the need for individual species identification. However, inconclusive, or even opposite dependencies between acoustic indices and animal biodiversity found in various studies suggest that their effectiveness is environmentally variable.Here we examined how three acoustic indices: Bioacoustic Index (BI), Acoustic Complexity Index (ACI) and Acoustic Diversity Index (ADI) predict bird species richness in a species-rich, lowland temperate forest in Europe – the Białowieża Forest. We recorded soundscape in early and late spring at 84 recording points. We analysed 72 1-min sound samples collected per recording point to evaluate how well acoustic indices predict bird species richness from the perspective of a single sound sample, survey and recording point and how they follow the daily pattern of singing activity.When we compared the values of acoustic indices with the number of bird species detected manually in 1-min sound samples, we found BI to best predict the bird species richness, independently of time in the season but variably across the day, while ACI and ADI showed weaker dependency, variable both seasonally and daily. The correlation between each index and number of bird species was stronger in the early part of the season. Averaged by survey or recording point, the acoustic indices correlated more strongly with the mean compared to the total bird species richness, and provided better estimation of bird biodiversity in the early than the late survey. At the level of the recording point, BI correlated most strongly with mean bird species richness (rho = 0.584), while ADI correlated most strongly with total bird species richness (rho = -0.347). Acoustic indices followed daily bird activity pattern, yet they provided greater values before the peak of the species richness estimated by manual spectrogram scanning and listening to recordings.In this study acoustic indices correlated moderately to strongly with the bird species richness, providing a useful tool for rapid estimation of bird biodiversity in temperate forests. However, daily and seasonal variation in effectiveness of acoustic indices should be taken into account in the analysis. Using the mean instead of the total number of bird species in comparisons improved the effectiveness of indices but measured different aspects of biodiversity.

Factors influencing habitat choice of bird species: a comparative study of the ornithofauna of a natural and an artificial wetland

Between 2019 and 2022, we studied the avifauna and environmental conditions of two wet-land habitats located in close proximity to each other in Transcarpathia (nearby to the village of Dyida, Zakarpatska Oblast, Ukraine)—one being a natural, currently protected but drying and highly degraded former bog (Tóvár Ornithological Reserve), whereas the other one being an ar-tificial pit lake (Lake Dyida). Lake Dyida is used as a beach and recreation area during the summer nesting season of birds. Both of these wetlands border with agricultural lands. Bird species that occur in both of the investigated habitats are affected by severe anthropogenic disturbances. A total of 27 795 individuals of 58 bird species from 34 families were observed in the two areas over the four study years. Results indicate that the species composition of the two study sites differed considerably, both on annual and seasonal basis. Seasonal precipitation totals strongly influence the current spatial ratios of terrestrial and waterbird species, and show a strong positive correlation with the seasonal total number of bird species. Maximum numbers of birds are recorded in spring and summer at Tóvár and in autumn and winter at Lake Dyida. In the case of Lake Dyida, these could partly be due to the autumn–winter appearance of migratory waterbirds and the end of the beach season. Despite the impact of numerous anthro-pogenic factors and habitat distrubances, the natural wetland is much more species-rich even in its degraded condition than the artificial wetland, which has been confirmed not only for bird species but also for plant species in the two areas. The obtained results revealed that duck spe-cies consider the deep-water pit lake as an alternative habitat during periods of drought, but for waders the great water depth makes this site less exploitable. In Europe, too, drying out due to seasonal precipitation shortages is an issue of increasing concern, especially for wetlands bea-cuse artificially maintained lakes and reservoirs cannot fully take over the role of natural lakes, marshes and bogs, which will have severe consequences for nature protection and species con-servation in the future.

Birds of Parque Nacional do Caparaó, Atlantic Forest, southeastern Brazil

Parque Nacional do Caparaó is located in the Serra do Caparaó in the southeastern region of Brazil. It lies on the border between the states of Espírito Santo and Minas Gerais. It is a large fragment of Atlantic Forest vegetation, with altitudinal variation from 630 to 2,892 m. We present an annotated list of bird species found in the park based on data collected from 2012 to 2018. We recorded 216 species, including 66 endemic, 22 threatened, and 17 newly recorded species. To complete the list of species, we added data available in several bibliographic sources and digital databases, bringing the total number of bird species in the park to 348 and including 98 endemic and 33 threatened species. This work is the first to present an updated list of birds for the park, and the data presented show the importance of this protected area for conservation of birds in the region.

Species richness of birds along a complete rain forest elevational gradient in the tropics: Habitat complexity and food resources matter

AbstractAimWe examined whether the available surface area, temperature, or habitat complexity (foliage height diversity index) determine species richness of birds (and species richness of individual feeding guilds) along a complete forest elevational gradient. Further, we focused on the relationship between species richness of insectivorous birds and the availability of their food resources.LocationElevational gradient (200–3,700 m) of Mt Wilhelm (4,509 m a.s.l.), Central Range, Papua New Guinea.TaxonBirds.MethodsWe collected data on bird communities at eight sites (500 m elevational increment) during three surveys encompassing both dry and wet seasons over a 2‐year period. We used point counts, mist‐netting, and random walks throughout a standardized area. We tested three predictors of diversity and all of their combinations, in conjunction with sensitivity analyses for spatial effects. Habitat complexity (foliage height diversity index) and temperature were locally measured; surface area available within 200 m elevational intervals was obtained using GIS software. We further locally surveyed insect biomass and related it to species richness of insectivorous birds.ResultsBirds displayed a monotonic decline in species richness (from 113 to 35 bird species) with increasing elevation, and a nested pattern of species loss. The observed patterns were best explained by habitat complexity for the insectivores, frugivore‐insectivores, and total number of bird species. The available surface area was the best predictor for frugivorous birds. The mean temperature had a high correlation with species richness of all birds and gave the best fit of species richness for insectivore‐nectarivores and pure nectarivores. The biomass of insectivorous birds correlated with the biomass of arthropods. We ruled out the possibility that the elevational pattern observed in birds could be driven by a single phylogenetic radiation.Main conclusionsWe observed species richness patterns correlate well with habitat complexity and mean temperature, but mean temperature was not ranked as high as expected. Our results thus challenge the generally expected high importance of temperature as a regulator of water availability, production, and biochemical process that influence species richness, and underscore the importance of vegetation structure and the food resources as the driver of observed species richness.

Современное состояние хищных птиц природного заповедника «Опукский»

This paper provides information on the status of Birds of Prey in the State Nature Reserve “Opuksky” from 2010 to 2018. As of December 1st of 2018, 261 bird species (77% of the total Crimean bird fauna) have been registered on the territory of the Reserve and adjacent territories, including 28 species of Birds of Prey (12% of the total number of bird species in the reserve), which belong to 12 genera. Only 10 species out of 28 (36%) nest relatively regularly on the studied territory (that includes Reserve and its surrounding areas).

Effect of temporal lakes on avifaunal composition at the Southeast of Isthmus of Tehuantepec, Oaxaca, Mexico.

Oaxaca hosts one of the greatest biodiversity in México, occupying first place in avian diversity compared to other regions of the country. However, the area is undergoing serious problems such as high defor- estation rates, soil erosion and over exploitation and extinction of species. These factors have all contributed to the current loss of biodiversity. Also, biological inventories are still incomplete. One of the least explored sites is the semiarid zone of Tehuantepec isthmus, around the locality of Santa Maria del Mar, Oaxaca, México. The area includes floodable grasslands, mangrove areas and dry forest, providing a range of potential habitats for different species. Our objective was to evaluate the effect of temporal lakes on spatial and temporal composition of the avifauna in Santa Maria del Mar, in order to generate information regarding this group within the region and the state, and to understand the importance of flood areas for resident and transitory birds. We conducted 12 avifauna surveys between July 2006 and June 2008, and established two transects of 2km length in each of four habitat types (beach, grassland, dry forest, and mangrove). We found a total of 75 species, corresponding to 16 orders and 30 families. Within an area of 26 km2, we significantly found 10.1% of the total number of bird species recorded for the entire state, and 6.6% of the total reported in Mexico. The families most repre- sented were: Ardeidae, Laridae and Scolopacidae. Over the entire study period, dry forest was the most diverse habitat; followed by mangrove, grassland and the beach. Of all the species recorded, 38.6% were found at the edge or in the temporal lakes. We found a significant difference in species composition between seasons in the grassland, but no difference in the other habitats. Our results showed a significant effect of temporary lakes on avian diversity during the wet season; it also demonstrated the importance of grassland conservation given its relevance for presence of waterbirds. We suggested a continued and more intense monitoring; and proposed the designation of the area as an Important Conservation Bird Area (AICA).

The fauna and vertical distribution of birds in Mount Qomolangma National Nature Reserve

From October 2010 to October 2012 (total 126 days), we used the line transect method combined with interviews applied during seven individual surveys to explore the bird resources of Qomolangma National Nature Reserve (QNNR). Based on the historical records and the present results, a total of 390 bird species belonging to 62 families and 18 orders, had been confirmed. Our results indicated that QNNR plays a vital and unique role in bird species preservation and scientific study, especially for endemic and endangered species. Species richness of both the Palearctic and Oriental realms were different, there was no overall significant difference (164 and 178, respectively). Species differences between the northern and southern slope of QNNR were especially remarkable. The northern slope was characterized with enriched endemic plateau species over small total number of bird species the southern flank held an abundance of bird species with complex composition. Moreover, on the southern slope, the peak of breeding birds richness occurred at 2,500~3,100 m a.s.l., supporting the mid-domain effect hypothesis. Meanwhile, as elevation increased, the richness of Oriental species decreased while that of Palearctic species increased. The percentages of Oriental and Palearctic species were similar at 3,100~4,000 m a.s.l.. Accordingly, we estimated that the boundary of Oriental realm and Palearctic realm was at 3,100~4,000 m a.s.l., and the species invasion from Palearctic to Oriental realm was more obvious. Perhaps most significantly, the specific distribution species along the vertical gradients also indicated their corresponding adaptation strategies.

Significant Impacts of the Water Level and Human Intervention on the Natural Habitats and Breeding Waterbirds in Marmara Lake

Habitat cover and change were analysed in the Marmara Lake to investigate the effects of water level and human intervention on the natural habitats and breeding waterbirds. Breeding Birds Surveys were applied to investigate breeding waterbirds and their breeding activities in 2008 and 2011. GIS, remote sensing techniques and various satellite images were used to determine distributions, surface areas, zonal centroids, and displacements of the habitats in 2000, 2008 and 2011. The total number of bird species with and without breeding evidence in 2008 and 2011 were compared with the Chi-Square test. Habitats in each UTM grid in 2008 and 2011 were compared with McNemar’s test. The impact of water level on habitats, number of breeding birds, and their breeding parameters were investigated using Spearman’s correlation analyses. The major habitats were open waters, reed beds, scrubs and woodlands, wet grasslands, and mudflats. Significant increases were observed in open waters, reed beds, and wet grasslands, but no significant change was observed for scrubs and woodlands. Out of 70 UTM grids, 69 and 48 grids corresponding to 95 and 75 observation points were surveyed in 2008 and 2011, and 34 different waterbirds were identified. The total number of breeding waterbirds significantly increased in 2011. Open waters were positively correlated with reed beds and negatively correlated with mudflats. Among 34 waterbird species, changes in the breeding parameters of 22 species were significantly correlated with the changes occurring in the major habitats. Our study demonstrates that changes in water level significantly affected the existence of key habitats and theirs distributions, resulting in significant changes in the number of breeding waterbirds and their breeding activities.

The avifauna of larger islands along the Kimberley coast, Western Australia

Bird observations were collected opportunistically on 24 islands along the remote Kimberley coast of Western Australia between 2007 and 2010. We present a summary of our observations, along with bird data collated from other sources, to provide baseline inventories for these islands. A total of 157 species were recorded during our survey. The inclusion of other records increased the total number of bird species known from these islands to 179, with species richness for individual islands ranging from 22 to 95 taxa. We found that, in general, more bird species were observed on larger islands. Island attributes most closely correlated with observed bird assemblages included the extent of rugged habitat, the number of habitats and temperature in the warmest month of the year. No bird species or subspecies are confi ned to the Kimberley islands. Only one threatened bird species, the northern subspecies of the Masked Owl (Tyto novaehollandiae kimberli ), is known to occur on the islands we sampled. Further surveys are required to better document the avifauna of these and other Kimberley islands and to improve our understanding of the biogeographical patterns of Kimberley island birds.

Avian Succession in Small Created and Restored Wetlands

We described the change in avian use over time in small created and restored wetlands in southeastern Wisconsin. Quantitative avian surveys were conducted in 28 sites ranging in age from 11 to 15 years and compared to data collected in the same sites in 1994. Bird species were categorized into ruderal, wetland, and oldfield habitat guilds. The density of bird use was compared between survey years. We tested for significant effects of wetland age, size, and landscape variables on avian use. The total number of bird species using the restorations increased by 35% over the 10-year period, although the average number of bird species recorded in each wetland during a single visit did not change significantly. There was also a substantial shift from wetland to oldfield habitat guilds resulting from a net loss of 5 wetland-dependent bird species and a net gain of 19 oldfield and 2 ruderal bird species. Mean bird density increased from 13.5 birds per hectare in 1994 to 58.2 in 2004. Our results suggest that although conservation wetlands and their associated buffers initially provide avian habitat for many wetland-dependent bird species, structural changes in the plant community over time create habitat increasingly favored by grassland/shrubland birds.

Long-term effects of fragmentation and fragment properties on bird species richness in Hawaiian forests

Forest fragmentation is a common disturbance affecting biological diversity, yet the impacts of fragmentation on many forest processes remain poorly understood. Forest restoration is likely to be more successful when it proceeds with an understanding of how native and exotic vertebrates utilize forest patches of different size. We used a system of forest fragments isolated by volcanic activity 153 years ago in Hawaii to examine how long-term fragmentation, as well as fragment size and structural features affect the richness of native and exotic bird species. The total number of bird species increased rapidly with forest fragment size, with most of the native species pool found in patches <3 ha. Smaller fragments were dominated by native bird species with several exotic bird species found only in the largest fragments, suggesting that exotic bird species in this landscape show greater area-sensitivity than native species. We used airborne scanning light detection and ranging (LiDAR) to assess whether fragment area was correlated with estimates of fragment vegetation volume as well as measures of tree height. Fragment area was highly correlated with vegetation volume, maximum tree height, and canopy height heterogeneity, and these variables were strong predictors of bird richness, demonstrating that remote sensing can provide key insights into the relationship between fragment structural attributes and biodiversity indicators. Overall, this work demonstrates the value of conserving small remnant mid-elevation forest patches for native birds in Hawaii. This work also provides insight into how newly created forest patches might be used by native and exotic bird species in Hawaii.

Thirty Years of Post-fire Succession in a Southern Boreal Forest Bird Community

Birds and vegetation were surveyed in a 9 ha plot in spring 1976 in a 73 y-old jack pine (Pinus banksiana) – black spruce (Picea mariana) forest in northeastern Minnesota. A 1368 ha wildfire burned across the area that autumn. The plot was resurveyed in 1977 and periodically through 2006. Before the fire, birds with the highest importance values were Blackburnian Warbler (Dendroica fusca), Ovenbird (Seiurus aurocapillus), Red-eyed Vireo (Vireo olivaceus) and Bay-breasted Warbler (D. castanea). Within 7 y following the fire, canopy tree cover decreased to near zero as fire-damaged trees died. Afterwards, the canopy began increasing, reaching 53% cover by 30 y. Shrub cover, 8% before the fire, peaked at over 70% two decades after fire, primarily as a result of dense jack pine and black spruce regeneration, and then decreased to 58% 30 y after fire. The total number of bird species using the area doubled the first year following the fire while the number of bird species with discernable territories decreased 40%. Thereafter, territorial species began increasing and 30 y after the fire the number exceeded the pre-fire richness by 60%. Overall, density of bird territories decreased nearly three-fold the first 3 y after the fire, but by year 30, was over 56% greater than in the pre-burn mature pine forest. Loss of canopy was related to a reduction in warbler and vireo diversity while increases in woody debris and near-ground vegetation were related to an increase in ground-brush foragers such as White-throated Sparrow (Zonotrichia albicollis) and Chipping Sparrow (Spizella passerina). Brown Creeper (Certhia americana) populations increased briefly as trees died, and for five years following fire there was an increase in woodpeckers and secondary cavity nesting species. At 7 to 10 y after fire, White-throated Sparrow, Magnolia Warbler (Dendroica magnolia), Chestnut-sided Warbler (D. pensylvanica), Nashville Warbler (Vermivora ruficapilla) and Mourning Warbler (Oporornis philadelphia) dominated. White-throated Sparrow continued to be the most important bird species through the first two decades, followed by Magnolia Warbler and Red-eyed Vireo. Thirty years after fire, the dominant birds were Nashville Warbler and Ovenbird, followed distantly by Veery (Catharus fuscescens) Swainson's Thrush (Catharus ustulatus), Least Flycatcher (Empidonax minimus) and Black-and-white Warbler (Mniotilta varia). Overall, bird species using the area after 30 y remained over 70% higher than in the mature forest before the fire.

Breeding season avifauna of prairie dog colonies and non-colonized areas in shortgrass prairie

Avian assemblages of black-tailed prairie dog (Cynomys ludovicianus) colonies were compared to those present at two types of non-colonized grassland, during the breeding season, in southwestern Kansas and southeastern Colorado. Relative abundances were quantified in 1996 during a period of drought and in 1997 during a period of above average precipitation. We detected fewer bird species at all sites in 1996 than in 1997, and the total number of bird species detected on prairie dog colonies was lower than that detected on both types of non-colonized areas during both years. Horned larks (Eremophila alpestris) had higher relative abundances on non-colonized sites in 1996, but were more abundant on prairie dog colonies in 1997. Lark buntings (Calamospiza melanocorys) and grasshopper sparrows (Ammodramus savannarum) were not recorded at the study sites in 1996, but appeared in high numbers in 1997. These two species, and western meadowlarks (Sturnella neglecta), had higher relative abundances on non-colonized sites in 1997 than on prairie dog colonies. A comparison of our results with those of other studies suggest that the effects of prairie dogs on associated biota might not be identical in all regions of the Great Plains, or under all environmental conditions.

Species‐Richness Correlations of Six Different Taxa in Swedish Seminatural Grasslands

Abstract: An important question in conservation biology is whether the biodiversity of different taxa is correlated. We studied the extent to which the number of species of six different taxa—plants, birds, butterflies, bumblebees, ground beetles, and dung beetles—in 31 Swedish seminatural grasslands covary, and whether species diversity can be related to habitat variables. During 1996 and 1997, we surveyed plants and animals with appropriate techniques for each taxa and mapped the grassland habitat. In general, correlations between taxa were few. Grassland plant diversity (currently used as an indicator for conservation value) was only significantly positively correlated to total bird diversity. Bumblebee diversity was significantly positively related to both total and grassland butterflies, whereas there was a significant negative relationship between grassland birds and dung beetles. Plants, birds, bumblebees, and butterflies showed significant similarities in patterns of species composition, as did birds, butterflies, grassland butterflies, and ground beetles. The total number of plants and both subsets of birds (total and grassland) were significantly positively related to area, whereas there was a significant negative association between area and dung‐beetle diversity. The diversity of both butterflies and bumblebees was significantly negatively related to the proportion of short‐grazed field layer. Bumblebees showed a positive relationship with junipers, whereas ground beetles and grassland birds were negatively associated with trees. The total number of bird species was positively influenced by the occurrence of shrubs. Our results suggest that neither the species richness of grassland plants nor that of any other of the surveyed taxa can be used as an indicator for total biodiversity in seminatural grasslands. The lack of similar patterns of species composition among taxa also makes it difficult to define functional groups with similar habitat demands. Until we have more detailed knowledge of the demands of species and taxa, it is important that we direct management efforts so that we provide a wide spectrum of grassland characteristics.

Avian Abundance in CRP and Crop Fields during Winter in the Midwest1

Abstract We compared the abundance and species composition of birds in Conservation Reserve Program (CRP) fields with the same aspects in row-crop fields during the winter (January and February) over several years (1992–1995) for six midwestern states (Indiana, Iowa, Kansas, Michigan, Missouri and Nebraska). Field techniques were standardized in all states. CRP fields consisted of either permanent introduced grasses and legumes (CP1) or permanent native grasses (CP2), and the plant species seeded in CRP fields differed within and among states. Vegetation characteristics of CRP fields varied considerably from state to state, but vertical density and total canopy cover (primarily grasses) were particularly high in Nebraska. Mean annual total bird abundance ranged from 0.1 to 5.1 birds per km of transect in CRP fields and from 0.1 to 24.2 in row-crop fields. The total number of bird species recorded in CRP fields in the six states ranged from 6 to 32; the range for row-crop fields was 8 to 18. The most abund...

庭園に飛来する鳥類の環境構造に対する選択性に関する研究

Numbers of bird species were counted in four Japanese gardens at Chiran town, Kagoshima Prefecture, from December 1992 to December 1993 every four weeks. The conditions of the place where birds came flying werestudied. Total number of bird species discovered in the gardens were twenty one. Among the birds, following eight species abounded in the gardens; Passer montanus, Hypsipetes amaurotis, Zosterops japonica, Emberiza spodocephala, Parus major, Cettia diphone, Turdus pallidus and Dendrocopos kizuki. Structures and set of conditions in the garden chosen by birds depended on bird species. H. amaurotis and Z. japonica mainly chose the surface of the tree crown of Camellia japonica with nectar-bearing flowers for feeding. E.spodocephala, C. diphone and T. pallidus chose the structures inner hedge and pollarded shrubs which were not crowded by leaves and stems for resting. P. major and D. kizuki chose the one standing high trees for feeding insects and resting. All species did not choose narrow spaces crowded by leaves and stems, such as Rhododendron indicum pollard

Conservation Value to Birds of Remnants of Melaleuca Forest in Suburban Brisbane.

The bird species composition of nine remnants of Melaleuca quinquenervia forest in NE Brisbane, Queensland, was censused from March 1992 to March 1993 to investigate the effect of forest fragmentation and fragment characteristics. Remnant area was a correlated with the total number of bird species and the number of raptors occurring, while understorey vegetation density was related to the number of forest and understorey bird species. The species composition of the M. quinquenervia remnants was compared with that of the Cooloola National Park and with that of eucalypt [Eucalyptus] remnants in lowland SE Queensland. Even the small M. quinquenervia remnants around Brisbane play an important role in conserving the avian fauna of the region by providing habitat and refuges for migrant, nesting, locally rate and uncommon species, and species not commonly found in other forest types. Future recommended management involves the maintenance of size, habitat diversity and understorey vegetation density, the prevention of disturbance and the preservation of swampy areas and ponds.

The importance of mires as breeding habitat for wetland birds in Sweden

During the last 15 years the bird fauna was censused on 2,250 km2 of mires, which is 10–15% of the estimated total area of larger, treeless mires (&gt;0.5 km2) in Sweden. The total number of bird species breeding on mires increases from 25 in the most southern region (Götaland) to 43 in the most northern region (N. Norrland), but more of the northern species breed at very low densities. Among taxonomic groups, species richness of wildfowl and shorebirds increases with latitude while that of passerines shows no clear trend. One possible explanation for the increased species diversity towards the north may be that northern mires generally have a more complex habitat structure, making more niches available. There was no general geographic pattern in the population density of different species. Wildfowl, birds of prey (including owls) and shorebirds (including the Crane) breed at higher densities in the north while passerines have lower densities. One reason for the higher breeding densities of wildfowl and shorebirds in the north is that mires there to a larger extent consist of fens than do mires in the south. Also, a lower nest predation in the north is a probable reason. Combining all species there was no trend in breeding density. Calculations of population sizes show that 25% of the 44 species recorded have breeding populations of more than 10,000 pairs while 25% have less than 1,000 pairs on mires. Estimates of population sizes in Sweden as a whole for all species breeding on mires show that 11 species have more than 50%, and four have more than 75% of their total Swedish population on mires. These species are especially interesting from a conservation point of view since they may be used as indicators of valuable mires.