Changes In Number Of Birds Research Articles

Sharp declines in observation and capture rates of Amazon birds in absence of human disturbance

Across the globe, unprecedented declines have been reported across a range of taxa. Among the most well documented are declines in bird populations, with most declines attributable to human activities such as deforestation and other alterations to habitats. There is increasing evidence that bird populations also have declined at sites within large expanses of relatively undisturbed lowland tropical forest, such as in Amazonia. Causes of such declines likely are varied and may be related to direct or indirect effects of climate change. Here, we use mist-net data and direct observations to examine changes in bird numbers over a 22-yr period on two 100-ha study plots in an Amazonian lowland forest of eastern Ecuador. As previously reported, capture rates experienced large declines from 2009 on; observation rates also showed large declines through 2013 but subsequently have shown no consistent trend up or down. Overall capture rates and observation rates are now approximately half the rates during the first decade. Most foraging guilds also declined over time, with declines particularly pronounced among insectivorous groups. With few exceptions, patterns of change were similar between plots suggesting a more general response rather than responses to local factors on each plot. Capture rates and observation rates of ∼90% of the most common species in both understory and canopy were lower during the latter part of the study, with only a few species (∼10%) showing increases. Similarly, large declines were seen in both canopy and understory mixed-species flocks. Large declines in bird numbers have been noted in other tropical sites that have conducted long-term population studies, including Panama and Brazil, suggesting a response to large-scale factors, such as climate change. While not yet documented, the consequences of losing approximately 50% of population abundance are likely substantial and could result in local extinction of rare species, altered species interactions and social organization, as well as declining ecological function and biotic integrity of these tropical forest ecosystems.

Modelling the recovery of resident shorebirds following a fox eradication program using citizen science data

Historically, the land-based threat to shorebird colonies on Phillip Island, Victoria, Australia, was fox predation. As a result, a fox eradication programme consisting of three phases: knock-down (i.e., 2006), clean-up (i.e., 2011), and post-eradication. In 2011 an effective knock-down was declared, signalling the beginning of the clean-up phase. The purpose of this research is to assess the recovery of six resident shorebird species on Phillip Island following fox removal. The statistical methodologies used are novel for assessing bird species population recovery following a successful predator eradication program. We used citizen science data from 2003 to 2017, extracted from the Atlas of Living Australia. The first analysis method used INLA modelling, which relied on a Negative Binomial distribution for bird counts to look for upward trends in shorebird populations during the fox eradication operation. The second method use changepoint analysis techniques to see whether successive phases of the eradication process were associated with changes in bird population numbers. Four of the six shorebird species investigated responded positively to reduced fox populations over the 15-year study, and all changepoint approaches consistently recognised the start of the clean-up phase, with less consistency identifying the start of the knock-down phase. Since 2006, the INLA models indicate a significant increase in the upward trend of shorebird populations for three of the six shorebird species investigated. Agreement across the four changepoint techniques indicates that changes in bird numbers were associated with the date of the eradication program's clean-up phase for all of these shorebird species. These results demonstrate some promise for these methods to monitor native species recovery during eradication programs.

Subarctic afforestation: Effects of forest plantations on ground‐nesting birds in lowland Iceland

Abstract Planting forests is a commonly suggested measure to mitigate climate change. The resulting changes in habitat structure can greatly influence the diversity and abundance of pre‐existing wildlife. Understanding these consequences is key for avoiding unintended impacts of afforestation on habitats and populations of conservation concern. Afforestation in lowland Iceland has been gaining momentum in recent years and further increases are planned. Iceland supports internationally important breeding populations of several ground‐nesting, migratory bird species that mostly breed in open habitats. If afforestation impacts the distribution and abundance of these species, the consequences may be apparent throughout their non‐breeding ranges across Europe and Africa. To quantify the effects of plantation forests on the abundance and distribution of ground‐nesting birds (in particular waders, Charadriiformes), surveys were conducted on 161 transects (surrounding 118 plantations) perpendicular to forest edges throughout Iceland. The resulting variation in density with distance from plantation was used to estimate the likely changes in bird numbers resulting from future afforestation plans, and to explore the potential effects of different planting configuration (size and number of forest patches) scenarios. Of seven wader species, densities of five (golden plover Pluvialis apricaria, whimbrel Numenius phaeopus, oystercatcher Haematopus ostralegus, dunlin Calidris alpina and black‐tailed godwit Limosa limosa) in the 200 m surrounding plantations were just under half of those further away (up to 700 m). Redshank Tringa totanus densities were lowest ≤150 m from the plantation edge while snipe Gallinago gallinago densities were 50% higher close to plantations (0–50 m) than further away (51–700 m), and no consistent effects of plantation height, diameter, density or type were identified. Plantations are typically small and widespread, and simulated scenarios indicated that total declines in bird abundance resulting from planting trees in one large block (1,000 ha) could result in only ~11% of the declines predicted from planting multiple small blocks (1 ha) in similar habitats. Synthesis and application. Planting forests in open landscapes can have severe impacts on populations of ground‐nesting birds, which emphasizes the need for strategic planning of tree‐planting schemes. Given Iceland's statutory commitments to species protection and the huge contribution of Iceland to global migratory bird flyways, these are challenges that must be addressed quickly, before population‐level impacts are observed across migratory ranges.

Long-term decline and geographical variation in the numbers of moulting Common Eiders Somateria mollissima in Shetland

ABSTRACT Capsule Numbers of moulting Common Eiders Somateria mollissima counted in Shetland during surveys from 1977 to 2019 decreased from approximately 14,500 to an estimated 3600 individuals, a 75% population decline. Aims To report results of extensive surveys of Eiders across Shetland during the annual complete moult period, review historical surveys, and evaluate long-term population changes and the possible underlying causes for change. Methods Extensive areas of coastal Shetland were surveyed for Eiders during the annual moult period from July to September, every one to five years from 1977 to 2019. Spatial sampling was variable between surveys from 1977 to 1993 but more systematic and standardised during all surveys from 1996 to 2019. Overall population change, changes in numbers of birds within areas categorised as either exposed or sheltered coast, and change in the proportion of adult males to females/juveniles were assessed. Results Surveys from 1977 to 1993 indicated a 55% decrease, from approximately 14,500–6500 individuals, and surveys from 1996 to 2019 showed a 45% decrease, from an estimated 6700–3600 individuals, indicating an overall population decrease of approximately 75% from 1977 to 2019. From 1996 to 2019, Eider numbers decreased in areas of exposed coast by approximately 90% but increased by at least 70% in the more sparsely populated sheltered areas, and the overall proportion of adult males to females/juveniles reduced by one-third. Conclusion From 1977 to 2019, a substantial decline of approximately 75% occurred in the Shetland Eider population at the time of moult. Shetland Eiders are not S. m. mollissima but morphologically and genetically akin to S. m. faeroeensis, the Faroese subspecies, the rarest subspecies worldwide, so this decline is of high conservation concern. Causes of the decline largely remain unknown, but ecological datasets on Shetland Eiders are few and detailed studies, including remote tracking of individuals’ movements throughout the year, would be worthwhile.

Recovery of Eurasian Coot Fulica atra and Great Crested Grebe Podiceps cristatus Breeding Populations in an Area Invaded by the American Mink Neovison vison

In birds, adaptations that mitigate predators' impact are usually ineffective in confrontation with introduced and rapidly expanding invasive non-native predators. As a consequence, bird populations often decline in the period following the time when predator population is established. Changes in bird numbers and nest spatial distributions in breeding populations of the Eurasian Coot Fulica atra and Great Crested Grebe Podiceps cristatus were studied in Mazurian Lakeland, northeastern Poland in 2002–2003 and 2016, and were analyzed with reference to the abundance of invasive American Mink Neovison vison, whose density declined since mid 1990s. The study was based on a census of breeding pairs and a search of nests at 31 lakes. The numbers of breeding Coots and Grebes increased 2.6-fold and 1.2-fold, respectively. In both study periods Grebes displayed a strong tendency to nest in the vicinity of human settlements and in colonies; however, the percentage of Grebe pairs nesting near settlements and in colonies decreased from 51% to 34% and from 73% to 57%, respectively. Coots also preferred to nest in the vicinity of human settlements. Distributions of their nests have not changed significantly over time: in both periods 55–60% of Coot nests were found in close proximity to human settlements and 13–19% in Grebe colonies. The obtained results suggest that breeding populations of the Coot and Great Crested Grebe can cope with the invasive American Mink, whose predation was considered to be the main reason for waterbird declines in Mazurian Lakeland at the end of 20th century.

Quantitative Characteristics of Seasonal Aspects of the Bird Population in the City of Kemerovo and Its Environs

This paper gives a quantitative assessment of seasonal aspects of the bird population on the basis of the data of year-round counts in the city of Kemerovo and its vicinity in 1999–2001. Seasonal changes in the total number of birds, species richness, dominating species, total biomass, amount of the energy transformed by birds, and their tier distribution and faunal composition are characterized and compared for all habitats surveyed. Differences in the seasonal dynamics of the bird population in the habitats belonging to residential and forest–field landscapes are assessed.

Higher-tier agri-environment scheme enhances breeding densities of some priority farmland birds in England

Agri-environment schemes (AES) are the main policy mechanism available to reverse the widespread losses of farmland biodiversity across Europe. Previous examples of AES enhancing the abundance of farmland birds have been restricted to targeted species recovery programmes, often with bespoke habitat management and high levels of advisory support for landowners. Here, we tested whether standard higher-tier AES agreements targeted at multiple species and with lower levels of advisory support than targeted species recovery programmes can enhance the breeding densities of farmland birds. Surveys of breeding birds were undertaken during 2008 and 2011 on 65 farms under higher level stewardship (HLS) and 21 farms lacking AES interventions, in three regions of England. After allowing for any impacts of predator control, changes in density were more positive on HLS farms in at least one region for six priority species. Five of the six species had mixed diets and were predominantly associated with field edges; the other (lapwing) probably responded to the provision of field-centre fallow plots. Changes in bird numbers were not consistently related to the extent of AES habitat provision. This is the first study to demonstrate that standard AES management without substantial ongoing advisory support can increase or maintain the densities of widespread declining species.

Hur påverkas fågelfaunan av upphörd betesdrift – data från en 26 år lång inventeringsstudie

The breeding bird fauna of a 1.6 km2 large grassland area in southwestern Sweden was monitored in 1987–2012, using the point count method. The area was grazed by approximately 500 cattle until 2006, and the grass height was then at most 10–15 cm except for higher tussocks. From 2007 onwards, when the grazing had ceased, the grass increased in height to 20–30 cm and became much thicker. The average number of bird species per year was 44.7 over the 26 year survey period. Numbers of some farmland birds such as Lapwing Vanellus vanellus, Skylark Alauda arvensis, Starling Sturnus vulgaris, and Linnet Carduelis cannabina decreased in the study area, following the general pattern in the whole of Sweden. Meadow Pipit Anthus pratensis, Corn Crake Crex crex, Whinchat Saxicola rubetra and Grasshopper Warbler Locustella naevia increased in the area, but decreased in Sweden in general over the same period. The local changes in bird numbers in the study area seem mainly to be caused by an increased grass height and thickness as a consequence of ceased cattle grazing.

ВИКОРИСТАННЯ ПРОГРАМИ «SIMPLY TAGGING» ДЛЯ ПРОГНОЗУВАННЯ ГУСТОТИ ПТАХІВ У ГНІЗДОВИХ БІОТОПАХ

<p>For the analysis of long-term observations data on dynamics of bird populations the most suitable methods could be the stochastic processes. Abundance (density) of birds is calculated on the integrated area of studied habitats. Using the method of autocorrelation the correlogram of changes in number of birds drawn during the study period in all the area. After that, the calculation of the autocorrelation coefficients and partial autocorrelation are performed. The most appropriate model is the mixed autoregressive moving average (ARIMA). Ecological significance of autoregressive parameters is to display the frequency of changes in the number of birds in the seasonal and long-term aspects. The sliding average is one of the simplest methods, which allows reject the random fluctuations of the empirical regression line. Validation of the model could be conducted on truncated data series (10 years). The forecast is calculated for the next two years and compared with empirical data. Calculation of correlation coefficients between the real data and the forecast is performed using non-parametric Spearman correlation coefficient. The residual rows of selected models are estimated by residual correlogram. The constructed model can be used to analyze and forecast the number of birds in breeding biotopes.</p> <p><em>Keywords: analysis, density, indirect methods, birds, Simply Tagging.</em></p> <p> </p>

МАТЕМАТИЧЕСКИЙ АНАЛИЗ ДИНАМИКИ ЧИСЛЕННОСТИ НЕКОТОРЫХ ОКОЛОВОДНЫХ ВИДОВ ПТИЦ ОСТРОВОВ СИВАША

<p>The problem of the mathematical analysis of dynamics of number of key colonial breeding waterbirds regarding to the islands of region is considered. The algorithm of an estimation of changes in number of birds is offered in scope of specific features of colonies and habitats. The data of long-term monitoring of island birds’ number have been analyzed according to proposed algorithm. On the basis of analysis results the necessity of use of the statistical indexes expressing the tendencies of changes in bird number and bird turnover is proved. For the key species of island communities the tendencies of changes in number are determined within the limits of researched region. The discussed technique of a complex estimation of breeding island bird dynamics is offered for the use at drawing up the management plans and development of nature protection actions with the purpose of conservation of bird diversity and their habitats.</p> <p><em>Key words: colonial birds, islands, dynamics of number, complex estimation</em></p> <p> </p>

Population trends of common birds in Estonia in 1983–2010

The paper presents the set-up and development of a common bird monitoring scheme in Estonia in 1983-2010. The point-count survey of widespread terrestrial bird species was undertaken to measure long-term population changes and to produce indicators of the condition of habitat types and the wider environment. The scheme has been mostly run by skilled volunteers of the Estonian Ornithological Society. The method applied is point counting on free- choice routes and without limiting recording distance. In the Estonian scheme, each count route consists of 20 points, with 5-minute stops at least 200 m apart. In total, 143 point count routes have been in use by 89 active birdwatchers and professional ornithologists in the course of 28 years. Yearly abundance indices for 87 bird species were calculated using TRIM software. The most evident changes in bird numbers were the declines detected in 1992-1996 among farmland species, and in 2007-2010 among farmland and woodland species. The long-term population trends (1975-2010) in four countries around the Baltic Sea depend on the migratory strategy of bird species. Among trans-Saharan migrants the proportion of declining species was much higher in comparison with short-distance migrants and sedentary species. A marked difference between these countries was found among sedentary bird species - with up to 2/3 of species with increasing trends in Finland and less than 1/3 in Denmark, Sweden, and Estonia. There is a growing interest in using the results of the scheme both at the national and the international scale (PECBMS).

Observations of seabirds at offshore wind turbines near Blyth in northeast England

Capsule No obvious effects were detected, except for reduced Cormorant Phalacrocorax carbo presence after construction. Aim To check for differences in the numbers and behaviour of seabirds following construction of two turbines 1 km offshore. Methods Shore‐based two‐hour watches were conducted several times per month during 26 months before turbine construction, seven months during construction, and 32 months after construction. Numbers, flight heights and directions of all passing seabirds were noted, as were weather and tidal conditions. No watches were made under darkness or in poor daytime visibility. Results In summer, numbers of Cormorants declined post‐construction, while Sandwich Terns Sterna sandvicensis and Great Black‐backed Gulls Larus marinus increased. Otherwise no meaningful changes in bird numbers and behaviour were recorded, and no collision mortality was witnessed during 352 hours of daytime watches post‐construction. Most seabirds flew below the height of the rotor blades. Conclusion Apart from possibly causing decline in summer usage of the locality by Cormorants, the turbines seem to have had no adverse effects on the local seabirds in the periods and conditions covered by our watches. We advise against extrapolating our findings to conditions of poor visibility or darkness, or to larger windfarms.

Migration Dynamics and Seasonal Variation In the Biometrics of the Eurasian Curlew (Numenius arquata) Migrating through the Lower Vistula Valley (N Poland) in Autumn

Migration Dynamics and Seasonal Variation In the Biometrics of the Eurasian Curlew (Numenius arquata) Migrating through the Lower Vistula Valley (N Poland) in Autumn The aim of this study was to present data on the phenology of autumn migration of the Eurasian Curlew passing the lower Vistula valley and to determine whether there is a difference in biometrics between early and late migrants, which may reflect different timing of migration of birds from different parts of the breeding range. Studies were conducted in the lower Vistula valley in 2003-2008. Median date of migration fell into 9-13 August pen-tade. The migration dynamics showed major day-to-day changes in bird numbers and almost all of observed flocks migrated without staying in the study area. Moreover, only one bird was caught twice during the season. It indicates that lower Vistula valley is not an attractive stopover site for Eurasian Curlews. There were significant differences in the total head lengths, bill lengths and body masses of birds caught in different ten-days periods with larger and heavier birds occurring towards the end of the study period (ANOVA, Neuman-Keuls test: p < 0.05 in all cases). The gradual increase in the total head and bill lengths and probably also in body mass indicates that bigger birds from the eastern part of the breeding range migrate later than smaller birds, which breed in the west. There were no significant differences in wing length, tarsus length and tarsus with toe length (ANOVA, Neuman-Keuls test: p > 0.05 in all cases). Subspecies N. a. arquata and N. a. orientalis have similar wing length and in this study there were no significant differences for this measurement between following decades of the studied period. Collected data suggest that the wing length, which had clearly bimodal distribution, should be the best linear measurements for sexing at least juvenile Eurasian Curlews.

Linking birds, fields and farmers

The dramatic decline in the presence of farmland birds during recent decades has provoked much attention in agri-environmental policy and ecological research. However, the still limited understanding of the socio-economical mechanisms that govern the decline in bird presence hampers the formulation of effective adjustments in land-use and farming practices that could support the return of birds to farmland, i.e. the required fine-tuning of management practices. As a consequence, the existing agri-environmental schemes that offer financial compensation to farmers for implementing generally simple and rather crude measures to stimulate the presence of birds have been limited in their effectiveness and subject to much debate. The objective of this paper is to provide a sociological appraisal of farmers’ experiences with meadow bird protection in a mainly dairy farming area in the Netherlands. The methodology combined visual map analysis, surveys, interviews with farmers and experts, and monitoring farmers’ discussions. The results allowed an assessment of (i) farmers’ views on historical changes in bird numbers in the area and the current distribution of bird nests, (ii) locally adjusted, fine-tuned management practices that were considered to be promising for protecting bird nests, (iii) the importance of farm management with ‘an eye for birds’, i.e. farmers and/or birdwatchers paying additional attention to the presence of nests and chicks before carrying out farming activities, and (iv) the views of key experts in the socio-institutional network in the case study area. The paper concludes that there are various promising options for fine-tuning farm management so it offers better bird protection, but it is expected that such measures will predominantly be adopted on less intensively managed farms.

Fruit tracking between sites and years by birds in Mediterranean wintering grounds

Knowledge of the ability of birds to track spatiotemporal variation in fruit distribution is essential for understanding plant‐frugivore interactions. Arguably, although total fruit availability sets an upper limit to the number of birds that can exploit a habitat patch, not all species can equally distribute abundance according to variation in fruit resources. To explore this, we studied bird and fruit abundance in 1999–2005 in Mediterranean scrublands and woodlands of southern Spain. We analysed whether changes of fruit abundance in eight different sites during six winters could predict numerical changes of a set of frugivorous passerines of the area (blackcap Sylvia atricapilla, Sardinian warbler S. melanocephala, robin Erithacus rubecula, song thrush Turdus philomelos and blackbird T. merula). We also investigated if all frugivores together tracked fruits better than individual species, thereby supporting a shared use of resources. Results showed strong inter‐specific differences. Only the most abundant species (blackcaps and robins) tracked the spatial patterning of food despite strong differences in the use of space (vagrant and territorial, respectively). This suggests plastic behaviour of territorial robins, with individuals changing from strictly territorial to wandering, a flexibility that would favour between‐site numerical arrangements according to food resources. Annual changes in bird numbers were independent of the availability of fruits, except for blackcaps, an abundant vagrant bird that tracked inter‐winter changes in fruit abundance. The abundance of blackcaps fitted the spatiotemporal patterning of fruit resources better than the whole guild of frugivorous birds, inconsistent with the idea that these species track together the changing availability of fruit resources.

Breeding Bird Community of a Primeval Temperate Forest (Białowieża National Park, Poland) at the Beginning of the 21stCentury

The 2000–2004 results of the mapping technique censuses carried out in permanent plots situated in three types of old-growth primeval BNP stands (ash-alder riverine, oak-hornbeam, mixed coniferous) are presented and compared with data gathered in the same plots in the late 1990s. These data supplement earlier observations in the BNP and extend the long-term set of data on the breeding bird numbers there to a 30-year uninterrupted series (1975–2004). Most community parameters, such as the composition of breeding avifauna, the species richness, and the make-up and cumulative share of dominants, have remained basically unchanged. The overall bird density has increased by 8–20% in different plots; in 2001 it reached the highest level within the 30-year study period. The increase was due to parallel increases in numbers of several species, widely differing in their nesting sites, food requirements and migratory habits — during this period 14 of the 26 most numerous species attained their highest numbers in the 30-year study period. Since numbers increased simultaneously in all the plots, the density differences across habitats remained the same, from the highest densities in riverine stands at the forest edge (up to 149 p/10 ha), through oak-hornbeam stands, to the lowest densities in the coniferous stands (54–56 p/10 ha). In most cases the numerical increases could not be attributed to changes in local environmental factors, such as food resources, or to detectable changes in habitat structure. The apparent lack of a relationship between the changes in bird numbers and the local situation suggests that factors acting on a larger scale (beyond the study area) could have been involved. Despite the directional changes in bird abundance observed in the Białowieża Forest, its breeding bird assemblage, when compared with the amplitude of changes recorded over the same period in other areas and habitats, stands out as an example of remarkable stability.

Five‐year evaluation of the impact of the Arable Stewardship Pilot Scheme on birds

Agri‐environment schemes could play a key role in the reversal of farmland bird declines. The effectiveness of the Arable Stewardship Pilot Scheme for delivering farmland birds was tested in a replicated, farm‐scale field trial, in two lowland farmland regions of England. Changes in numbers of birds over five years were compared between control and scheme farms. In East Anglia, productivity of Grey Partridges Perdix perdix was significantly higher on scheme than on control farms, although such an effect was not seen in the West Midlands where the species was rarer. At the field scale, wintering granivorous passerines and Skylarks Alauda arvensis responded to stewardship habitats (options) such as stubble and wild bird cover designed specifically to benefit them. However, at the farm scale, winter bird counts were higher on scheme than control farms only in the West Midlands, and not in East Anglia where the availability of set‐aside and features managed for game in the wider landscape was higher. In the absence of other high‐quality habitat, arable options are effective at providing good quality habitat, but the amount needed to exert an influence at the bird population level remains uncertain.

Bird and rat numbers on Little Barrier Island, New Zealand, over the period of cat eradication 1976–80

Passerines were monitored on Little Barrier Island over 15 years (1975–89) spanning the period (1976–80) when feral cats were eradicated from the island. All birds seen and heard were recorded while walking three transects representing an altitudinal range from near sea level to approximately 550 m above sea level. Analysis of variance statistics were used to test for differences in bird numbers between transects and between years. Bird species were examined by transect to test for changes in numbers over time. Three species had increased on some transects, and two species had decreased on some transects, but it was difficult to attribute changes in bird numbers to the one cause which we were able to study: reduced cat numbers. Examination of numbers of individuals of 14 species recorded between transects showed significant differences for some individual species, but not for all species grouped together. Four species did not show any significant differences between transects. This study demonstrates different patterns in bird distributions on Little Barrier Island which cannot be understood from these data. Index traplines were set for Pacific rats or kiore (Rattus exulans) between 1977 and 1984, before and after cat eradication. Rat numbers fluctuated widely, and there were no significant differences that could be attributed to the changes in cat numbers.

Changes in the Distribution and Abundance of Columbian Sharp-Tailed Grouse in Washington

Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) were historically found in shrub steppe, meadow steppe, steppe, and deciduous shrub communities throughout much of eastern Washington. The current range, consisting of 8 relatively small, isolated, populations, is less than 3% of historic range. Information collected since 1954 indicates 58% of 107 known lek complexes are currently vacant. Many of the vacant lek complexes (53%) are in areas where sharp-tailed grouse have been extirpated since 1954. Based on annual changes in number of birds counted on lek complexes, the number of sharp-tailed grouse in Washington declined by about 92% since 1954 to 858 birds in 1998. Historic and recent declines of sharp-tailed grouse appear linked to dramatic declines in quantity and quality of native habitat.

Effects of Grasshopper Control Programs on Rangeland Breeding Bird Populations

We investigated the effects of grasshopper control methods on breeding bird populations in western rangelands. We estimated bird densities on 13 treated and 11 untreated sites before and after grasshopper control operations. Four different treatments were used in these applications: malathion, sevin-4-oil, carbaryl bait and Nosema locustae bait. There were few differences among the 4 treatments in their effects on bird community parameters (total bird density, and species richness, diversity, or evenness). Bird community parameters did not differ between spray and bait applications but sample sizes were small for bait treatments. When data from all treatments were combined for analysis, there was no difference in any of the bird community parameters between pre- and post-treatment samples. Densities of western meadowlarks (Sturnella neglecta), however, were significantly lower on treated than untreated sites 10 and 21 days after treatment. We found no relationship between changes in bird numbers 21 days post-treatment and either the size of the area treated or the date of treatment (i.e., early or late in nesting season). Malathion is an acetylcholinesterase (AChE) inhibitor, but brain AChE levels in birds collected on sites treated with malathion showed no significant inhibition. These results suggest that grasshopper integrated pest management treatments generally have little effect on breeding bird communities but some insectivorous bird species may decline on rangeland treated with broad-spectrum insecticides because of reduction in food base. Pesticide applications that have adverse impacts on birds and other nontarget wildlife that prey on grasshoppers may be counterproductive to long-term integrated pest management goals.