Rare Bird Species Research Articles

The Weekend Bias in Recording Rare Birds: Mechanisms and Consequencess

The creation of species lists is a quick and relatively cheap method to evaluate the biodiversity value of some sites and as such they are used in various conservation actions. Species lists typically focus on recording rare and endangered species, usually by volunteers who watch birds during their free time, which may lead to an uneven distribution of observations during the week. We examine whether and to what extent a weekend bias exists in the recording by volunteers of rare bird species. We used a database summarizing 1679 records throughout Poland of 154 rare bird species represented by 2433 individual birds. The proportion of individual birds recorded during weekends was significantly higher than expected by chance. The proportion of records of rare birds that were made during weekends varied from 32.4% in July to 54.9% in November and the weekend bias was lowest during the summer holidays (i.e. July and August). Species varied in their weekend bias, however species size and conspicuousness scores did not explain species-specific weekend bias. Species richness as a function of sampled individuals did not differ between weekends and weekdays. We suggest that potential biases caused by increased weekend recording need to be considered when comparing abundances based on lists from different sites or seasons, e.g. in studies on the effect of weather on birds. Our results suggest that the weekend effect is not qualitative but only reflects changes in sampling effort across the week and therefore records from weekends and weekdays are comparable in term of species composition.

The influence of habitat fragmentation on genetic diversity of a rare bird species that commonly faces environmental fluctuations

Habitat loss and fragmentation is one of the main causes of biodiversity loss. Rare species are generally thought to be more sensitive to habitat fragmentation than common ones as small populations become even smaller. We did a population genetic study on a rare bird, the Worthen's sparrow Spizella wortheni which is endemic to semi‐arid and arid regions of northeast Mexico. Its population numbers suffer greatly from the transformation of grassland into farmland that leads to a patchy distribution with locally small population sizes. Our data show that its genetic diversity is nevertheless high, few to no differentiation between study localities was found, and gene flow was high. Although we can not exclude that is too early to see an impact on the genetic level, we think that these results might be explained by the species’ biology: like many other birds living in arid areas, the Worthen's sparrow has a nomadic life style; depending on local conditions individuals flexibly move between areas. This behavior could enhance their ability to find suitable habitat patches in a fragmented landscape. Our results imply that nomadic behavior, which is an adaptation to high temporal variability in environmental conditions, may make species more resilient to spatial variability caused by habitat fragmentation. This insight contributes to identifying common factors such as nomadism that predict a species’ sensitivity to habitat fragmentation.

ЗАМЕТКИ О ПТИЦАХ ОХОТСКОГО РАЙОНА ХАБАРОВСКОГО КРАЯ

New observation data describe the distribution, number and status of 10 rare and understudied species of birds in Okhotsky district, Khabarovsky Krai. The Great Egret Casmerodius albus, Red-breasted Goose Branta ruficollis, Mandarin Duck Aix galericulata, Baer's Pochard Aythya baeri, King Eider Somateria spectabilis, Watercock Gallicrex cinerea were registered in the studied territory for the first time.

Industrial wetlands as refuges for bird biodiversity conservation in the forest-steppe zone

The rare bird fauna of industrial wetlands has been studied in the forest-steppe zone of European Russia during the nesting period. A total of 146 species have been recorded, including 40 rare species listed in the regional Red Data Books. Facts of their nesting (in many cases, exceptional in the region) have been revealed. Evidence is presented for the significance of industrial wetlands for the conservation and propagation of rare bird species.

Awifauna wodno-błotna środkowej Wisły w okresie lęgowym: wpływ działalności człowieka na rozmieszczenie, liczebność i bogactwo gatunkowe

The inventory of birds was conducted in the years 2005-2010 on the Vistula River section between Dęblin (388 km of the river) and Podwierzbie (435 km of the river). The study area includes a southern section of the European Ecological Natura 2000 Site in Poland PLB140004 „Middle Vistula River Valley” (IBA, PL083). In most areas the Vistula flows here within unregulated or relatively little modified riverbed, having features of natural, lowland, braided river. Sandy islands and braid bars within the main channel, steep banks, and old riparian afforestation create the unique breeding habitats of the Vistula River Valley. Especially the river channel habitats provide suitable breeding sites for many rare bird species, constituting some of them the key-breeding sites. There are, however, fragments of several kilometers, where people transformed the Vistula River in a more visible way (Table 1). These are, among others: an urban section within Dęblin boundaries (km 388-393 of the river), a fragment adjacent to Kozienice Power Plant (km 421-426), and the area, where since 2007 gravel for the industry has been mining from the river bottom (km 426-431). The aim of this inventory was the comparison of richness and abundance of breeding bird species associated directly with the river channel on fragments mentioned above. It will allow us to estimate soberly how very the intensity of human utilization of the river affects the distribution of avifauna of the Vistula, determining the richness and abundance of valuable and/or endangered species breeding in a given area.

The impact of industrial pollution on the ecosystem of Réghaia Lake (Algeria)

This study lies within the framework of the anti-pollution action plan of Reghaia Lake. This lake, partially fed by the ground water of Mitidja, is regarded as an area of international importance because it is the last vestige of Mitidja. It is currently the only wetland in the biogeographic area of Algiers, thus making it a stopover for migratory birds after their crossing of the Mediterranean. The area is characterized by a great diversity of flora and fauna, and a large variety of ecosystems. Reghaia Lake has a considerable wealth of flora estimated at about 233 listed plant species: the equivalent of 13% of the North Algerian flora. The area is also home to four species of rare birds, three of which are classified as threatened on the red list of the IUCN. Because of this diversity, it was registered on the Ramsar list in November 2002 during the eighth meeting of the Conference of the Contracting Parties to the Ramsar Convention in Valencia, Spain. The lake, which has a surface area of 75 ha, is also...

Multiple lines of evidence support the recognition of a very rare bird species: the Príncipe thrush

The Gulf of Guinea thrush Turdus olivaceofuscus is endemic to the islands of Sao Tome´ (nominate olivaceofuscus) and Pr ´ incipe (subspecies xanthorhynchus). Rela- tionships between the two island taxa, originally described as two different species, are uncertain. This problem has been difficult to resolve due to the scarcity of information from Pr ´ incipe birds. A focused effort to find birds from Pr ´ incipe resulted in new observations, the first records of its song, and in the capture of four individuals, which provided new data for analyses. We obtained additional data from museum specimens. Our analyses indicate that the two populations differ substantially in size, bill shape and bill, eye and leg coloration as well as in several plumage characteristics. In addition, xanthorhynchus utters a low call of a type not previously recorded in the genus Turdus. Genetic evidence corroborates the phenotypic evidence: both taxa constitute clearly independent evolutionary lineages (2368 bp from the mitochondrial markers ND2, ND3 and cytochrome b (cyt-b) from four individuals of each population). Genetic divergence between the taxa (cyt-b: uncorrected: 6.4%; corrected: 8.8%) suggests that they may have been isolated for over 4 Myr. These results support the split of T. olivaceofuscus into two species: Sao Tomethrush T. olivaceofuscus and Pr ´ incipe thrush Turdus xanthor- hynchus. The latter is a very rare species, restricted to the most inaccessible parts of Pr ´ incipe Island. Phylogenetic inference favoured the African thrush Turdus pelios as the closest living relative to the Gulf of Guinea species.

A Low False Negative Filter for Detecting Rare Bird Species From Short Video Segments Using a Probable Observation Data Set-Based EKF Method

We report a new filter to assist the search for rare bird species. Since a rare bird only appears in front of a camera with very low occurrence (e.g., less than ten times per year) for very short duration (e.g., less than a fraction of a second), our algorithm must have a very low false negative rate. We verify the bird body axis information with the known bird flying dynamics from the short video segment. Since a regular extended Kalman filter (EKF) cannot converge due to high measurement error and limited data, we develop a novel probable observation data set (PODS)-based EKF method. The new PODS-EKF searches the measurement error range for all probable observation data that ensures the convergence of the corresponding EKF in short time frame. The algorithm has been extensively tested using both simulated inputs and real video data of four representative bird species. In the physical experiments, our algorithm has been tested on rock pigeons and red-tailed hawks with 119 motion sequences. The area under the ROC curve is 95.0%. During the one-year search of ivory-billed woodpeckers, the system reduces the raw video data of 29.41 TB to only 146.7 MB (reduction rate 99.9995%).

Intracontinental spatial connections of lesser white-fronted geese (Anser erythropus) from mountain subarctic regions of the Central Palearctic

The lesser whitefronted goose, Anser erythropus L., 1758, is an endangered species included in the Red Data lists of IUCN and Russia. Its total abundance is apparently no more than 16000 ind. (Morozov and Syroechkovskii, 2002). Among measures aimed at the conservation of rare species of migratory birds, of great significance are the study and monitoring of condi� tions along their migration routes. Therefore, in 2006 and 2007 we performed the first study on interconti� nental spatial connections of A. erythropus geese nest� ing on the Putorana Plateau, a major but as yet poorly known segment of the species range. Regions, dates, and methods of bird tagging and tracking. The Putorana Plateau, which forms the northwestern tip of the Central Siberian Highland, is the central part of the A. erythropus nesting range. The plateau is a basalt massif with flat peaks (up to 1500 a.s.l.) located in the northern taiga subzone. To study A. erythropus migrations, we used the method of satel� lite telemetry. Between July 23 and August 2, 2006, six molting adult birds attending their broods on Dyup� kun (Kureiskii) Lake, in the southwestern part of the plateau, were tagged with plastic collars fitted with sat� ellite transmitters. For technical reasons, we failed to receive signals from three transmitters as soon as in late August, but movements of the remaining three birds were successfully tracked during the following 8 months. The results of tracking are summarized in the table, and the general scheme of movements (tracks) of the three geese tagged on the Putorana Plateau is shown in the figure. Migrations in Western Siberia and northern Kaza�

Estimated dates of recent extinctions for North American and Hawaiian birds

Series of sighting records - the years in which a species has been recorded - can be used to infer whether species have gone extinct, and when extinctions occurred. We compiled sighting records for 52 rare bird species, subspecies, and distinct island populations from North America and Hawaii, 38 of which proved adequate for such analyses. Using a data set that combines non-controversial sight records with those for which physical evidence exists, no populations were judged likely to be extant, including those that have not been declared extinct. The 'alalawas the only species with a 95% confidence interval around the extinc- tion date that extended beyond 2009, suggesting that this population is the least unlikely to be extinct. Although all are probably extinct, populations were ranked according to their likelihood of persistence, so that any future searches can be prioritized to minimize the risk that resources are spent on extinct spe- cies. Estimated extinction dates spanned the period from the 1840s-2000s, with evidence for a peak in the early 1900s. On average, only about 4 years passed between a species' last sighting and its estimated extinc- tion date, and the 95% confidence intervals around extinction dates extended 9-26 years after the last sight- ing. Long gaps between sightings were very rare. Mean and median gap sizes between consecutive sightings within sighting records were 2.5 and 0 years, respectively. Gaps between the last and penultimate sightings were smaller than average gap sizes earlier in sighting records. Finally, a non-parametric method that can be calculated with more limited data proved a weak substitute for using more complete sighting records.

Chapter III. Consequences of the Chernobyl Catastrophe for the Environment

Air particulate activity over all of the Northern Hemisphere reached its highest levels since the termination of nuclear weapons testing—sometimes up to 1 million times higher than before the Chernobyl contamination. There were essential changes in the ionic, aerosol, and gas structure of the surface air in the heavily contaminated territories, as measured by electroconductivity and air radiolysis. Many years after the catastrophe aerosols from forest fires have dispersed hundreds of kilometers away. The Chernobyl radionuclides concentrate in sediments, water, plants, and animals, sometimes 100,000 times more than the local background level. The consequences of such a shock on aquatic ecosystems is largely unclear. Secondary contamination of freshwater ecosystems occurs as a result of Cs‐137 and Sr‐90 washout by the high waters of spring. The speed of vertical migration of different radionuclides in floodplains, lowland moors, peat bogs, etc., is about 2–4 cm/year. As a result of this vertical migration of radionuclides in soil, plants with deep root systems absorb them and carry the ones that are buried to the surface again. This transfer is one of the important mechanisms, observed in recent years, that leads to increased doses of internal irradiation among people in the contaminated territories.Plants and mushrooms accumulate the Chernobyl radionuclides at a level that depends upon the soil, the climate, the particular biosphere, the season, spotty radioactive contamination, and the particular species and populations (subspecies, cultivars), etc. Each radionuclide has its own accumulation characteristics (e. g., levels of accumulation for Sr‐90 are much higher than for Cs‐137, and a thousand times less than that for Ce‐144). Coefficients of accumulation and transition ratios vary so much in time and space that it is difficult, if not impossible, to predict the actual levels of Cs‐137, Sr‐90, Pu‐238, Pu‐239, Pu‐240, and Am‐241 at each place and time and for each individual plant or fungus. Chernobyl irradiation has caused structural anomalies and tumorlike changes in many plant species. Unique pathologic complexes are seen in the Chernobyl zone, such as a high percentage of anomalous pollen grains and spores. Chernobyl's irradiation has led to genetic disorders, sometimes continuing for many years, and it appears that it has awakened genes that have been silent over a long evolutionary time.The radioactive shock when the Chernobyl reactor exploded in 1986 combined with chronic low‐dose contamination has resulted in morphologic, physiologic, and genetic disorders in every animal species that has been studied—mammals, birds, amphibians, fish, and invertebrates. These populations exhibit a wide variety of morphological deformities not found in other populations. Despite reports of a “healthy” environment in proximity to Chernobyl for rare species of birds and mammals, the presence of such wildlife is likely the result of immigration and not from locally sustained populations. Twenty‐three years after the catastrophe levels of incorporated radionuclides remain dangerously high for mammals, birds, amphibians, and fish in some areas of Europe. Mutation rates in animal populations in contaminated territories are significantly higher and there is transgenerational genomic instability in animal populations, manifested in adverse cellular and systemic effects. Long‐term observations of both wild and experimental animal populations in the heavily contaminated areas show significant increases in morbidity and mortality that bear a striking resemblance to changes in the health of humans—increased occurrence of tumor and immunodeficiencies, decreased life expectancy, early aging, changes in blood and the circulatory system, malformations, and other factors that compromise health.Of the few microorganisms that have been studied, all underwent rapid changes in the areas heavily contaminated by Chernobyl. Organisms such as tuberculosis bacilli; hepatitis, herpes, and tobacco mosaic viruses; cytomegalovirus; and soil micromycetes and bacteria were activated in various ways. The ultimate long‐term consequences for the Chernobyl microbiologic biota may be worse than what we know today. Compared to humans and other mammals, the profound changes that take place among these small live organisms with rapid reproductive turnover do not bode well for the health and survival of other species.

10. Chernobyl's Radioactive Impact on Fauna

The radioactive shock when the Chernobyl reactor exploded in 1986 combined with chronic low-dose contamination has resulted in morphologic, physiologic, and genetic disorders in every animal species that has been studied--mammals, birds, amphibians, fish, and invertebrates. These populations exhibit a wide variety of morphological deformities not found in other populations. Despite reports of a "healthy" environment in proximity to Chernobyl for rare species of birds and mammals, the presence of such wildlife is likely the result of immigration and not from locally sustained populations. Twenty-three years after the catastrophe levels of incorporated radionuclides remain dangerously high for mammals, birds, amphibians, and fish in some areas of Europe. Mutation rates in animal populations in contaminated territories are significantly higher and there is transgenerational genomic instability in animal populations, manifested in adverse cellular and systemic effects. Long-term observations of both wild and experimental animal populations in the heavily contaminated areas show significant increases in morbidity and mortality that bear a striking resemblance to changes in the health of humans--increased occurrence of tumor and immunodeficiencies, decreased life expectancy, early aging, changes in blood and the circulatory system, malformations, and other factors that compromise health.

Major current and future gaps of Brazilian reserves to protect Neotropical savanna birds

We tested the prediction that climate-driven changes might alter bird species composition in reserves of the Cerrado region of Brazil. First, we modelled the current distributions and the potential future projections of 38 endemic or rare bird species. We used eight modelling techniques within the BIOMOD computational framework in an ensemble-forecasting approach to reach a consensus scenario. Then we compared current and future (2046–2060) distributions under different scenarios (reserve size and bird dispersal) with the current Brazilian reserve system to assess the adequacy of protection (representation) of each species and detect gaps in their protection. Finally, to identify areas with high probability of occurrence of several species, we calculated cumulative climatic suitability of all 38 species for both current and future scenarios. None of the 38 species is covered under any current or future scenarios, revealing that the current reserve system is highly inefficient in conserving the analyzed bird species. The implementation of new reserves to cover species in current and future climate scenarios is recommended in areas in the south-eastern part of the Cerrado region and in the mountains of east Brazil. Due to the already high land use of the southeast region of the Cerrado, the application of non-traditional conservation measures should be evaluated.

The science of bird conservation

Colin Bibby (1948–2004) was the quintessential bird conservation biologist. Over his career, he served as lead scientist at two of the world's largest bird conservation organizations, the Royal Society for the Protection of Birds, and BirdLife International. His contributions encompassed detailed autecological studies of rare bird species such as the Dartford Warbler Sylvia undata (e.g. Bibby 1978) and Fuerteventura Stonechat Saxicola dacotiae (e.g. Bibby and Hill 1987), a sweeping synthesis of the techniques of bird conservation science (Bibby et al. 1992, 2000), and pioneering contributions in conservation planning such as the Endemic Bird Areas concept (ICBP 1992).

ORIGINAL ARTICLE: Comparison of predictor sets for species richness and the number of rare species of butterflies and birds

AbstractAim Accurate inventories of biota are typically restricted to few locations within an extensive region. Accordingly, effective planning must involve some form of surrogate measures coupled with spatial modelling. We conducted a simultaneous comparison of models of both species richness and the number of rare species using three types of surrogates (indicator species, vegetation composition and structure, and topoclimate) as predictors. We evaluated each type of surrogate alone and in combination with others.Location Data for our analyses were collected from 1996–2004 in three adjacent mountain ranges in the central Great Basin (Lander and Nye counties, Nevada, USA), the Shoshone Mountains, Toiyabe Range and Toquima Range.Methods Data on species richness and species composition of butterflies and birds and measures of vegetation composition and structure were obtained in the field. Topoclimatic variables were derived by GIS from digital sources and satellite images. We used Poisson regression with Bayesian model averaging to predict species richness and the number of rare species. We compared the expected prediction success of all models on the basis of internal and external validation trials.Results Same‐taxon indicator species were the most accurate predictors of species richness and of the number of rare species of butterflies and birds. Cross‐taxon indicator species and topoclimate variables were reasonably accurate predictors of species richness of butterflies and birds and of the number of rare butterfly species. Although vegetation variables were more effective for predicting species richness and number of rare species of birds than of butterflies, they were the least accurate predictors overall.Main conclusions Although indicator species may provide the most accurate predictions of species richness, their practical value, like any surrogate measure, depends greatly on ecological considerations and land‐use context. In general, the ability to predict numbers of rare species based on any set of candidate predictors was weaker than the ability to predict species richness, which may result from the high degree of stochasticity that often characterizes distributions of rare species. Our statistical approach for objective examination of different candidate predictors can help ensure that selection of species‐richness surrogates in any system is scientifically reliable and cost‐effective.

Interactive factors leading to dying-off Carex tato in Momoge wetland polluted by crude oil, Western Jilin, China

Momoge wetland is an internationally important wetland not only because it is a habitat for many rare bird species but also because it is an internationally important stopover for some rare global migratory bird species. However the petroleum exploitation in wetland has brought about many environmental problems. One of the most severe problems is crude oil pollution, which has caused the dying-off Carex tato and imposes great threat on survival of rare birds. This work studied the factors that caused the dying off of Carex tato. The results showed that death of Carex tato was the result narcosis toxicity of alcohols, intermediate biodegradation products of crude oil, on the root tissue, and the fragmentization of cuticle of leaves by light components of crude oil volatized from soil surface. However, the mechanism involved was much more complex and three interactive factors including crude oil pollution of soil, long-term drought and poor permeability of soil were responsible for the dying-off of Carex tato grassland. The distribution of crude oil in soil profile was characterized with high concentrations at top silty layer and the layer below root zone and low or no crude oil at root zone layer. This distribution was relative to root system characteristics and rhizospheric biodegradation. In root zone, substantive oxygen could be transported to root zone through dense root system and well developed aerenchyma. The crude oil in root zone was easily biodegraded by aerobic rhizosphere microbes. However, some toxic intermediate products, such as some alcohols, was sealed in root zone due to poor permeability of the top soil layer and the deeper soil layer and they had lethal effects on root tissue. Above ground, low molecular components of crude oil in top soil layer was easily volatized into atmosphere during long-term drought. Some of the volatized components were adsorbed onto leaves. SEM analysis showed that these components destroyed the leaves by fragmentization of cuticle of leave. This study also shows that although wetland has natural attenuation of pollutants, natural attenuation of pollutants by natural wetland should not be overemphasized. This attenuation function may lose under some conditions such as long-term drought and poor soil texture.

Upland raptors and the assessment of wind farm impacts

Government targets on renewable energy coupled with anthropogenic constraints on development have resulted in a surge in proposals to locate wind farms in upland areas, where they may conflict with the wellbeing of scarce or rare bird species including raptors. European and UK legislation demand that the effects of wind farm developments, both individually and in combination, be assessed to determine the level of impact on these species. The principle adverse effects of wind farms on raptors, as for other terrestrial birds, potentially involve disturbance (displacement or barrier impacts) or collision fatality. Few long‐term studies on such effects of wind farms have been undertaken. We review available research results on displacement of raptors, which primarily involve foraging birds, and conclude that most studies indicate that displacement appears to be negligible, although some notable exceptions occur and more research is needed. There is also a need for better understanding of the numbers of birds likely to be killed through collision with turbine rotors at the site level in order to inform planning decisions, although models of bird distribution at several spatial scales can be used to circumvent potential difficulties when locating turbines. Modelling approaches have also been developed that attempt to quantify the theoretical risk of collision. One such approach, the Band model, is a valuable tool for impact assessment and its use is now widespread in the UK. However, there are practical problems associated with gathering the data required to run the model and numerous assumptions must be made concerning bird behaviour. This can lead to deficiencies in the input parameters which potentially have a large effect on the model outputs. Hence, we make recommendations for potential improvements, such as quantifying error in flight height estimation, training of observers in acuity skills, quantifying bird detection‐distance functions, and research on factors influencing activity budgets and flight behaviour. In addition, the model outputs are usually adjusted to take account of turbine avoidance by birds and this aspect of birds’ behaviour is poorly understood. As a result of these limitations, collision predictions are only indicative, and more reliable in some situations, and for some species, than others.

Avian botulism at a sugar beet processing plant inSouth Moravia (Czech Republic)

An episode of mortality in waterbirds occurred on a sedimentation reservoir with effluents from the sugar beet processing plant at Hrusovany n.J. (South Moravia, Czech Republic) in summer 2003: tens of black-headed gulls (Larus ridibundus), several lapwings (Vanellus vanellus), one little ringed plover (Charadrius dubius), one ruff (Philomachus pugnax), one wood sandpiper (Tringa glareola), and two avocets (Recurvirostra avosetta) died. One of the two avocets and the plover, local breeders, were examined and found positive for Clostridium botulinum type C toxin by use of the toxin-neutralization test. Avocet is classified as a rare bird species according to Red Book data and is listed as critically endangered species in theCzechRepublic, and is therefore protected. Avian botulism can occasionally cause deleterious effects to waterbird fauna and its protection.

Observações sobre aves granívoras (Columbidae e Emberizidae) associadas à frutificação de taquaras (Poaceae, Bambusoideae) na porção meridional da Cadeia do Espinhaço, Minas Gerais, Brasil

We present the results of observations on the birds associated to the seeding of two bamboo species in southern Espinhaço Range, Minas Gerais, Brazil. The sooty grassquit (Tiaris fuliginosa – Emberizidae) was recorded feeding on seeds of Parodiolyra micrantha (Kunth) Davidse & Zuloaga. Further, T. fuliginosa and the blue ground-dove (Claravis pretiosa – Columbidae) were recorded in another area, apparently associated with the seeding of P. micrantha. The uniform finch (Haplospiza unicolor – Emberizidae) was a common species in an area dominated by Chusquea attenuata (Döll) L. G. Clark. Although H. unicolor was not observed feeding on bamboo seeds, we presume that the concentration observed was due to the massive seeding of C. attenuata at Serra do Caraça, since it is not a common bird species in this area. Possibly, the absence of threatened and rare bird species previously recorded as associated to bamboo seeding is related to the fragmentation of forests and capture for illegal trade.

Mapping a forest mosaic – A comparison of vegetation and bird distributions using geographic boundary analysis

Many areas of ecological inquiry require the ability to detect and characterize change in ecological variables across both space and time. The purpose of this study was to investigate ways in which geographic boundary analysis techniques could be used to characterize the pattern of change over space in plant distributions in a forested wetland mosaic. With vegetation maps created using spatially constrained clustering and difference boundary delineation, we examined similarities between the identified boundaries in plant distributions and the occurrence of six species of songbirds. We found that vegetation boundaries were significantly cohesive, suggesting one or more crisp vegetation transition zones exist in the study site. Smaller, less cohesive boundary areas also provided important information about patterns of treefall gaps and dense patches of understory within the study area. Boundaries for songbird abundance were not cohesive, and bird and vegetation difference boundaries did not show significant overlap. However, bird boundaries did overlap significantly with vegetation cluster boundaries. Vegetation clusters delineated using constrained clustering techniques have the potential to be very useful for stratifying bird abundance data collected in different sections of the study site, which could be used to improve the efficiency of monitoring efforts for rare bird species.