Ground-nesting Birds Research Articles

Spatial interrelations between raccoons (Procyon lotor), red foxes (Vulpes vulpes), and ground-nesting birds in a Special Protection Area of Germany

In this study, we examine the spatial interrelation between different carnivore species (Carnivora, Mammalia) and ground-nesting birds in a Special Protection Area (SPA) in Brandenburg, Germany. Camera- and live-trapping of carnivores during an 18-month period revealed that the SPA hosts most mesocarnivore species that occur in Germany. Since raccoon (Procyon lotor), red fox (Vulpes vulpes), and domestic cat (Felis silvestris f. catus) showed highest abundance-activity indices, we used GPS telemetry for a detailed analysis of spatial behavior of nine raccoons and five red foxes over a 22-month period. Spatial distribution patterns showed a strong difference between both species: raccoons showed a clear preference for reed swamps and shrub swamps, clustering in high concentrations along the edges of water bodies. Although this behavior is likely due to the high and year-round availability of aquatic food sources, overlap of raccoon core areas with high densities of wetland birds likely results in a high level of sublethal predation effects particularly on waterfowl breeding in reed beds. Red foxes showed much more evenly distributed movement patterns and a high intraspecific variability in habitat preference, revealing a general preference for woodlands and an avoidance of wetlands. Thus, predation pressure by foxes on ground-breeders seems to be lower and focusing on grassland-associated bird species in close proximity to woodlands. Consequently, our study highlights the need for a differentiated view on the predatory potential of particular mesocarnivore species on the endangered bird species in the SPA, leading to future management implications with a focus on swampland habitats.

Does the use of nest materials in a ground-nesting bird result from a compromise between the risk of egg overheating and camouflage?

ABSTRACTMany studies addressing the use of nest materials by animals have focused on only one factor to explain its function. However, the consideration of more than one factor could explain the apparently maladaptive choice of nest materials that make nests conspicuous to predators. We experimentally tested whether there is a trade-off in the use of nest materials between the risks of egg predation versus protection from overheating. We studied the ground-nesting Kentish plover, Charadrius alexandrinus, in southern Spain. We added materials differing in thermal properties and coloration to the nests, thus affecting rates of egg heating, nest temperature and camouflage. Before these manipulations, adults selected materials that were lighter than the microhabitat, probably to buffer the risk of egg overheating. However, the adults did not keep the lightest experimental materials, probably because they reduced camouflage, and this could make the nests even more easily detectable to predators. In all nests, adults removed most of the experimental materials independently of their properties, so that egg camouflage returned to the original situation within a week of the experimental treatments. Although the thermal environment may affect the choice of nest materials by plovers, ambient temperatures were not so high at our study site as to determine the acceptance of the lightest experimental materials.

Common Terns Sterna hirundo incubating Common Garden Snail shells Helix aspersa on Rockabill Island

Many ground-nesting bird species have been observed incubating foreign objects in their nests (Mellink 2002). Pine cones, golf balls, guano, hermit crabs, mammalian bones and many more objects have all been recorded in bird nests (Knight & Erickson 1977; Mellink 2002; Langlois et al. 2012). A study by Conover (1985) showed that 10% of Ring-billed Gull Larus delawarensis and 6% of California Gull L. californicus nests contained a foreign object. These foreign objects were more similar in size and shape to the gull eggs than to randomly selected pebbles. Little Terns Sterna albifrons have been observed incubating egg-like pebbles for several weeks on two separate occasions at a breeding colony in Kilcoole, Co. Wicklow, Ireland (Farrelly 1990). Several hypotheses have been put forward to explain this behaviour. Coulter (1980) suggested that foreign objects may act as an incubation stimulus. Many tern and gull species, unlike other birds, have three brood patches not one (Gochfeld 1976; Reid 1987). Coulter (1980) conducted incubation studies of several species of gulls suggesting that birds incubating three eggs sat for longer periods of time, resettled less frequently, have a shorter incubation period and a higher hatching success than birds on either fewer eggs or more. He speculated that gulls are highly adapted for three-egg clutches whereby the foreign objects provide an important stimulus for incubation behaviour when there are less than three eggs (Beer 1961; Beer 1965; Baerends et al. 1970; Coulter 1980). Alternatively, the mistaken-food hypothesis suggests that a predatory bird brings a foreign object back to the nest, regurgitates the object and then proceeds to incubate it, mistaking it for one of its own eggs (Sugden 1947; Twomey 1948). A third hypothesis is that the foreign object is mistaken by the bird for one of its own eggs and rolled into the nest, in this scenario the foreign object is likely to have originated from close to the nest (Conover 1985).

Curation Conservation

Curation Conservation Andrea Appleton (bio) I Feral cats can jump as high as six feet. Juvenile mice can fit through a hole smaller than an aspirin tablet. Stoats move so quickly they can scale an electric fence between high voltage pulses and land on the other side unscathed. We have learned these things by trying to fence these animals out. We are fencing them out to atone for our mistakes. Human beings have rearranged the matrix of life on Earth, sometimes on purpose and sometimes by accident. In the nineteenth century, the British wanted to blow bugles and hunt foxes in Australia just like they did on their Yorkshire estates, so they shipped some over. The foxes still live there in vast numbers, devouring numbats and wallabies. Captain Cook accidentally left rats on tropical islands throughout the Pacific. Rats love nothing better than the egg of a ground-nesting bird. Whalers and explorers like Cook often had cats on board to control the rats; many disembarked and discovered that naïve island birds made for an easier supper. Invasive predators have contributed to more than half of all bird, mammal, and reptile extinctions. What can we do? We cannot herd together all the foxes and dispose of them. We cannot poison all the rats. Only very brave souls dare propose killing that most beloved of creatures, the cat. So we are beginning to fence in natural areas and fence out invaders. In Australia, a new enclosure to protect native animals from hungry cats, foxes, and other invaders goes up every year, on average. Federal, state, and municipal governments, NGOs, local environmental groups, and even individuals erect them. Last year, a nonprofit organization completed the world's largest, encompassing an area thirty times the size of Central Park. New Zealand, South Africa, and the United States have installed miles of predator-proof fencing. There are fences in the city and fences in remote deserts. There are fences to protect lizards and fences to protect snails. One fence crosses forty-two streams, with special gates to let fish in and out. The predators patrol the perimeter of these enclosures, sniffing, waiting. A tree could fall and break a fence, someone might leave a gate open, a kangaroo could [End Page 181] jump on the top rail and crush a fence section like a tin can. It takes less than twenty-four hours after a fence break for the rats to start streaming in. II When I was a kid, I watched a lot of "bear shows." That's what my family called television shows about nature, like Marty Stouffer's Wild America. At the time, Marty Stouffer was a celebrity among nerds, but his reputation isn't so great anymore. PBS did an investigation and discovered that he staged a lot of episodes. Once, his team filmed wolves chasing and killing a deer. The animals turned out to be within an enclosure, so the deer couldn't get out. A prey-proof fence, I guess. Filmmakers still regularly trick wildlife into camera-friendly behaviors. They put M&Ms in the carcass of a dead animal and send in trained "wild" animals to find them. They pester wild animals until they do something interesting. (One team of filmmakers reportedly smeared Bengay cream on a beaver's anus to get it to move around.) They rearrange footage to give it drama and a narrative arc. And they produce a lot of sound effects in the studio. In the right hands, a pair of gloves can sound like the flapping wings of a bird. III Here are a few things technology currently allows us to know about a tagged wild animal without leaving the office: Where the animal is at all times How warm or cold the animal is When an animal is pregnant or giving birth When an animal is interacting with another tagged animal When an animal has begun hibernating When an animal has died Here are a few of the tools we use to control invasive predators: Artificial perfumes designed to attract specific predators Poison bait targeted at specific predators Traps powered by gas-fired pistons that can kill twenty...

Predation on artificial ground nests in relation to abundance of rodents in two types of forest habitats in the Tatra Mountains (southern Poland)

Context The breeding success of ground-nesting birds is strongly related to the predation rate. Many predators feed primarily on rodents when the densities of rodents are high and change to alternative prey (eggs or young birds) when the main prey populations decrease. Aims During a 3-year study, predation on an artificial nest was related to population dynamics of small mammals in coniferous and deciduous forests in the Tatra Mountains (western Carpathians). Methods Small mammals were captured using the live traps. In deciduous forest habitats, we placed 36 traps and, in coniferous forest habitats, we placed 18 traps. In total, 174 artificial nests imitating broods of hazel grouse (Tetrastes bonansia) were located randomly in both types of forest habitat between 2012 and 2014. Predators of the artificial nests were identified by camera-traps at 87 nests. Key results Most of the artificial nests were lost to predation by mammals. The most numerous species of rodents in both types of forest habitat were the yellow-necked mouse (Apodemus flavicollis) and the bank vole (Myodes glareolus). A significant decrease in the number of rodents was followed by a considerable increase of predation on artificial nests. There were no significant differences in the rates of predation between the two forest-habitat types. Conclusions Our results support the alternative prey hypothesis and suggest that the breeding success of ground-nesting birds in the forests of the Tatra Mountains varies strongly from year to year, depending on the abundance of rodents. Implications Increasing of rodents’ density may result in lower predation pressure on eggs of ground-nesting birds. This finding may help modify recommendations for conservationists and forest managers to optimize their effort to save populations of Galliformes.

The new faces of nest predation in agricultural landscapes\u2014a wildlife camera survey with artificial nests

European populations of many ground-nesting farmland birds have declined in recent decades. Increases in predator populations and nest predation may play an important role in this decline, along with habitat loss. However, the role of various predators has often remained unclear. We conducted a study with artificial nests and wildlife cameras (n = 104) in agricultural landscapes during 2015–2016 in South Finland. Our trials formed a 400-m wide gradient from forest to field. The aim of our study was to monitor nest survival and nest predators in a spatial and temporal scale. We tested the effect of distance to the forest and nest visibility to nest predation. During an 8-day period, 39.4% of the artificial nests were predated. Fifty percent of the predators were birds, 40% mammals, and 10% remained unknown. The three dominant predators of our artificial nests were the raccoon dog (Nyctereutes procyonoides) with 11 nests and the hooded crow (Corvus corone cornix) and the magpie (Pica pica) with 10 depredated nests each. Our analysis indicates that avian predators preyed upon nests in open fields further away from the forest edge, whereas mammalian predation concentrated closer to the forest edge. Predation occurred more likely at the beginning of the survey and nest survival increased as days passed. Our study highlights the efficiency of using wildlife camera traps in nest predation studies. We also suggest that the ongoing expansion of alien predators across Europe may have a greater impact on ground-nesting bird populations than previously anticipated.

Nest site taphonomy of colonial ground-nesting birds at Bowdoin National Wildlife Refuge, Montana

ABSTRACT Nesting localities of extant birds and reptiles may provide taphonomic models for interpreting nesting sites of ancient archosaurs. Here we describe assemblages of nesting gulls (Larus delawarensis and L. californicus), American white pelicans (Pelecanus erythrorhynchos), and double-crested cormorants (Phalacrocorax auritus). Seventy nests yielded 2752 skeletal elements and 2308 eggshells. Most material was located inside the nest for gulls and consisted of osteologically mature gull bones and pelican eggshell. Pelican and cormorant nesting material were located outside the nest, with higher percentages of juvenile avian bone. Eggshell concave up and down ratios on the surface of gull nests compared closely to predated assemblages. Pelican and cormorant surface ratios were approximately 50:50, suggesting trampling by altricial young. Weathered bones in the subsurface of cormorant and pelican nests and layers of predated eggshell in gull nests suggest multi-year accumulations. The amount of material associated with the nests and the age of the nester’s bones provides a means of distinguishing altricial and semi-precocial nesting sites. Nesting grounds for gulls with semi-precocial young yielded less skeletal material but a higher proportion of mature gull bones, whereas the large assemblages with altricial pelican and cormorant nests were dominated by prey items and their own young.

Deceptive nest defence in ground-nesting birds and the risk of intermediate strategies.

Nest predation is an important determinant of reproductive success and ground-nesting birds exhibit a variety of nest defence strategies to mitigate the risk. Many small-bodied, ground nesting birds rely on deceptive behaviours such as injury-feigning to reduce nest predation: we call this behaviour active deception. However, active deception may entail risks to adults, and passive deceptive behaviour, where individuals effectively sneak away from the nest by flushing at long distances, may be an alternative means of avoiding nest predation. We provide a simple model to demonstrate that these tails of the flush distance distribution could minimize predation risk; an intermediate strategy of moderate flush distances means that birds flush more often than with short-distance flushes, and once flushed, the nest is more easily located than for long-distance flushes. We tested this model using two species of ground nesting shorebirds, the White-rumped Sandpiper (Calidris fuscicollis) and the Red Phalarope (Phalaropus fulicarius). We demonstrate that short-distance flushes are associated with active deception and intermediate-distance flushes are associated with an increased risk of nest predation. However, we found no evidence that this potential selective pressure against intermediate strategies has produced a bimodal distribution of nest defence traits. The heritability of defence behaviours, or the ability of individuals to learn, is unknown and other factors such as energetic constraints or risks to adults might also influence flush distances and defence behaviours.

Incubating Upland Goose (Chloephaga picta) differential response to livestock, human, and predator nest disturbance

ABSTRACT The Upland Goose (Chloephaga picta) is a ground-nesting bird that has suffered a precipitous population decline in the last 60 years. We monitored Upland Goose nests with camera traps in S...

Individual egg camouflage is influenced by microhabitat selection and use of nest materials in ground-nesting birds

Camouflage is a widespread strategy to avoid predation and is of particular importance for animals with reduced mobility or those in exposed habitats. Camouflage often relies on matching the visual appearance of the background, and selecting fine-scale backgrounds that complement an individual’s appearance is an effective means of optimising camouflage. We investigated whether there was an active selection of microhabitats and nest materials in three ground-nesting birds (pied avocet, Kentish plover, and little tern) to camouflage their eggs using avian visual modelling. Plovers and avocets selected substrates in which their eggs were better camouflaged, and that choice was done at an individual level. Terns have lighter, less spotted eggs, and while they did select lighter background than the other species, their eggs were a poor match to their backgrounds. The worse matching of the tern eggs was likely due to a compromise between thermal protection and camouflage because they breed later, when temperatures are higher. Finally, the addition of nest materials improved egg camouflage in terms of luminance, although the materials reduced pattern matching, which may be associated with the different roles that the nest materials play. Active selection of substrates at an individual level may be crucial to improve nest success in species that nest in exposed sites. Many bird species nest on the ground at sites with no vegetation cover where their nests are exposed to visual predators. We studied whether individual females chose nest substrates that improved the camouflage of their eggs. Using images of nests and avian vision modelling, we found that the choice of nesting substrates in two species was done at the individual level, so that egg camouflage was optimised. In addition, such species were even able to improve egg camouflage by the addition of materials into the nests. However, this pattern was not observed in another species with paler and less spotted eggs, which may reflect a trade-off between camouflage and overheating of eggs because it breeds later in the season. Although individuals may try to choose substrates in which their eggs are better camouflaged, other factors that compromise offspring survival may hamper this.

Importance of Old Forest Stands for Diversity of Birds in Managed Pine Forests – A Case Study from Augustów Forest (NE Poland)

We assessed the assemblages of birds inhabiting pine-dominated managed forest, aged between 1–5 years and above 140 years. Birds were counted on study plots representing eight different phases to the forest's development, with nesting, foraging and migratory guild categories recognised. Numbers of bird species and population densities, both increased markedly with stand age (respectively r = 0.988 and r = 0.936, P < 0.001). While numbers of ground-nesting bird species failed to correlate with stand age, successively older stands did support ever-greater proportions of species in the assemblage that nested in tree crowns (r = 0.976, P < 0.005) or tree holes (r = 0.833, P < 0.005). Raptors were most abundant in forest at the oldest stages of growth, and there was an age-gradient-related increase in the shares of both plant-eating species (r = 0.952, P < 0.005) and raptors (r = 0.764, P < 0.005). Resident birds were most numerous in the oldest forest. PCA for ten selected variables (relating to guild type) showed that the two principal components explained almost 98% of the variation among groups of bird guilds in relation to forest age. On the basis of their suitability for birds it was possible to distinguish three categories of stand by age group, of which the first encompasses the initial stage, the second a broad interval involving middle-aged stands of between 16 and 140 years, and the third forest more than 140 years old. The presence of the oldest stands of all can thus be seen to play a very important role in maintaining high-diversity populations of birds in managed forest.

Evaluating the efficacy of a landscape scale feral cat control program using camera traps and occupancy models

The impact of introduced predators is a major factor limiting survivorship and recruitment of many native Australian species. In particular, the feral cat and red fox have been implicated in range reductions and population declines of many conservation dependent species across Australia, including ground-nesting birds and small to medium-sized mammals. The impact of predation by feral cats since their introduction some 200 years ago has altered the structure of native fauna communities and led to the development of landscape-scale threat abatement via baiting programs with the feral cat bait, Eradicat. Demonstrating the effectiveness of broad-scale programs is essential for managers to fine tune delivery and timing of baiting. Efficacy of feral cat baiting at the Fortescue Marsh in the Pilbara, Western Australia was tested using camera traps and occupancy models. There was a significant decrease in probability of site occupancy in baited sites in each of the five years of this study, demonstrating both the effectiveness of aerial baiting for landscape-scale removal of feral cats, and the validity of camera trap monitoring techniques for detecting changes in feral cat occupancy during a five-year baiting program.

Avian parental behavior and nest success influenced by temperature fluctuations

Behavioral adjustments and parental decisions during reproduction can influence the thermal environment at nests, yet our understanding into how environmental factors (i.e., temperature and precipitation) constrain an adult's ability to balance self-maintenance and incubation demands is limited. To expand our understanding of how species respond to environmental factors, we investigated the reproductive ecology of two ground-nesting species (northern bobwhite [Colinus virginianus] and scaled quail [Callipepla squamata]) in a region (i.e., the Southern Great Plains) prone to thermal variability (i.e., extreme hot and cold temperatures). Specifically, our objective was to examine how temperature and precipitation directly influenced behavioral adjustments (i.e., off-bout duration, frequency, and nest attentiveness) and parental decisions (i.e., nest site selection), and indirectly influenced nest fate. Overall, we found that parents chose to nest in sites that were significantly cooler in temperature than randomly selected sites, and parents further altered the thermal environment experienced by embryos through incubation behavior. Daily precipitation and average ambient temperature and/or their interaction best predicted incubation behaviors, yet each species differed in the timing (i.e., morning vs. evening), frequency, and duration of off-bouts. Furthermore, successful nests were associated with cooler nest site temperatures for bobwhite and warmer nest site temperatures for scaled quail. Our finding of relatively stable (35.5 °C) incubation temperature for developing embryos of both species suggests that ground-nesting birds are able to regulate microclimate through behavioral adjustments and parental decisions even under extreme temperature fluctuations. Nevertheless, the ability for a ground-nesting species to effectively modify behavioral adjustments and decisions may be altered during long periods of enhanced physiological and environmental stress.

Increased nest predation near protected capercaillie leks: a caveat against small reserves

Protecting animal aggregation sites is intuitively an efficient conservation approach, particularly for threatened species in fragmented landscapes. However, the appropriate scale of protection depends on accompanying threats, such as predator attraction to the same aggregation sites, to which the target species may need to respond by moving to alternative habitat patches. We performed experiments using artificial ground nests around protected capercaillie leks in commercially managed forest landscape in Estonia. We considered two scales: the landscape up to 3 km from the lek centre, and among 10–30-ha forest compartments, which differed in predator abundance. We found that nest predation significantly declined with distance from the lek. Nests were depredated by multiple mammalian and avian predator species and total predator abundance explained most of the between-forest variation in predation rate. Our results indicate that, in this hemiboreal area, (i) ground nest predation is largely determined by landscape-scale distribution of predators and (ii) predators can aggregate at capercaillie leks. The implication is that lek-centred habitat protection used for the capercaillie and other grouse may be ineffective unless the peripheral habitat quality and predator abundance are specifically addressed. More generally, predation pressure can be a serious problem in small set-asides within hostile landscapes for threatened ground-nesting birds.

Pen trial of estrogen-induced conditioned food aversion to eggs in raccoons (Procyon lotor)

Aversive conditioning is a promising but unproven non-lethal approach to reducing mammalian depredation on the eggs of ground-nesting birds, terrapins and sea turtles. This research tested the efficacy of oral estrogen concealed in a bland carrier as an aversive agent for wild-caught raccoons (Procyon lotor) under controlled conditions. Nine treatment group raccoons were given six estrogen-injected eggs every other day during a 14-day treatment phase, and then given a combination of two estrogen-injected eggs, two fresh eggs, and two carrier-only injected eggs every other day during a 14-day challenge phase. Nine control group animals received six carrier-only injected eggs every other day during the treatment phase, and then two fresh eggs and four carrier-only injected eggs every other day during the challenge phase. All treatment animals exhibited a conditioned food aversion (CFA) after 1–8 egg feedings (15–116 mg of estrogen per kilogram of body mass). All later sampled at least a few eggs, but they consumed fewer eggs than the control animals during both the treatment phase (p < 0.001) and challenge phase (p < 0.001). No raccoon could distinguish treated from untreated eggs during the challenge phase (p = 0.740); the treatment was undetectable by visual or olfactory cues. We observed no conspicuous changes in the feeding activity, behavior or demeanor of the treatment animals. Treatment and control animals ate (p = 0.629) and drank (p > 0.05) comparably. Treatment animals gained less mass than control animals (p = 0.013), but there was no apparent relationship between estrogen intake and mass change (p = 0.912). Testes of treatment males were similar in volume and mass (p = 0.712) to those of control males. Treatment animals experienced higher frequencies of abnormal feces (p < 0.005) and dermatitis (p = 0.001) than control animals. A treatment female died during the trial from an aborted late-term pregnancy, probably induced by the estrogen. Necropsies revealed no obvious tissue or organ damage from estrogen exposure. The conditions of this pen trial provide a conservative test of the potential for using an estrogen-induced CFA as a management tool for reducing egg consumption in the wild. Ingestion of 20–80 mg kg−1 of estrogen delivered over 1–4 days would be sufficient to bring about a reduction in egg predation using this method. A full-scale field trial of estrogen is likely to be productive under circumstances where all of the target population is subject to treatment.

Activity of potential predators of European hare (Lepus europaeus) leverets and ground-nesting birds in wildflower strips

The population decline of the European hare (Lepus europaeus) in Switzerland is generally attributed to low leveret survival. A significant intensification of agricultural practices led to a landscape transformation that reduced leveret survival by increasing negative factors such as predation pressure. Habitat improvement by means of wildflower strips has yielded some positive effects on European hare population trends, probably by improving food supply and providing year-round cover from predation. For this study, remote cameras were used to examine relationships between landscape and wildflower strip variables and the frequency of predator visits to wildflower strips as well as the probability of them visiting core areas of the strips. Of a total of 1586 visits of potential predators to wildflower strips, 91% were mammals and 9% were birds. Predators were more frequently observed at the edges of the wildflower strips than in their cores (72% of visits by mammalian predators and 76% by avian predators were at the edge). The results revealed that the frequency of observing predators was negatively correlated with adjacent crop height and the distance of the wildflower strip from settlements, roads and forests or hedgerows. The probability of a predator penetrating the core of the wildflower strip was negatively correlated with the vegetation cover, especially with the cover of wood, herbaceous plant species and teasel (Dipsacus fullonum). Appropriate management of wildflower strips by considering their spatial placement, creating low margin to surface area ratios and promoting heterogeneous wildflower structure can thus lead to reduced predator pressure on leverets as well as on ground-nesting birds.

Phenology largely explains taller grass at successful nests in greater sage-grouse.

Much interest lies in the identification of manageable habitat variables that affect key vital rates for species of concern. For ground‐nesting birds, vegetation surrounding the nest may play an important role in mediating nest success by providing concealment from predators. Height of grasses surrounding the nest is thought to be a driver of nest survival in greater sage‐grouse (Centrocercus urophasianus; sage‐grouse), a species that has experienced widespread population declines throughout their range. However, a growing body of the literature has found that widely used field methods can produce misleading inference on the relationship between grass height and nest success. Specifically, it has been demonstrated that measuring concealment following nest fate (failure or hatch) introduces a temporal bias whereby successful nests are measured later in the season, on average, than failed nests. This sampling bias can produce inference suggesting a positive effect of grass height on nest survival, though the relationship arises due to the confounding effect of plant phenology, not an effect on predation risk. To test the generality of this finding for sage‐grouse, we reanalyzed existing datasets comprising >800 sage‐grouse nests from three independent studies across the range where there was a positive relationship found between grass height and nest survival, including two using methods now known to be biased. Correcting for phenology produced equivocal relationships between grass height and sage‐grouse nest survival. Viewed in total, evidence for a ubiquitous biological effect of grass height on sage‐grouse nest success across time and space is lacking. In light of these findings, a reevaluation of land management guidelines emphasizing specific grass height targets to promote nest success may be merited.

Predation risk of artificial ground nests in managed floodplain meadows

Nest predation highly determines the reproductive success in birds. In agricultural grasslands, vegetation characteristics and management practices influences the predation risk of ground breeders. Little is known so far on the predation pressure on non-passerine nests in tall swards. Investigations on the interaction of land use with nesting site conditions and the habitat selection of nest predators are crucial to develop effective conservation measures for grassland birds.In this study, we used artificial nests baited with quail and plasticine eggs to identify potential predators of ground nests in floodplain meadows and related predation risk to vegetation structure and grassland management.Mean daily predation rate was 0.01 (±0.012) after an exposure duration of 21 days. 70% of all observed nest predations were caused by mammals (Red Fox and mustelids) and 17.5% by avian predators (corvids). Nest sites close to the meadow edge and those providing low forb cover were faced with a higher daily predation risk. Predation risk also increased later in the season. Land use in the preceding year had a significant effect on predation risk, showing higher predation rates on unmanaged sites than on mown sites. Unused meadows probably attract mammalian predators, because they provide a high abundance of small rodents and a more favourable vegetation structure for foraging, increasing also the risk of incidental nest predations. Although mowing operation is a major threat to ground-nesting birds, our results suggest that an annual removal of vegetation may reduce predation risk in the subsequent year.

Stronger response of farmland birds than farmers to climate change leads to the emergence of an ecological trap

Climate change is triggering adaptation by people and wildlife. The speed and magnitude of these responses may disrupt ecological equilibria and potentially cause further biodiversity losses, but this has rarely been studied. Species inhabiting human-dominated landscapes may be particularly negatively affected by human adaptations to climate change. This could be, for example, the case of ground-nesting farmland birds, a group of highly vulnerable species that may be impacted by shifts in the timing of mechanical farming operations in response to climate change. Here we aim to explore whether trends in phenology of breeding ground-nesting birds differ from those of farming practices, and whether differences lead to the emergence of phenological mistiming with detrimental consequences to the birds. To achieve our objective, we ran linear mixed effects models using a 38-year dataset on onset of farming practices (i.e. sowing dates) and laying date of two endangered ground-nesting farmland birds (Northern lapwing and Eurasian curlew) in Finland. We found that timing of farming practices advanced slower than birds nesting phenology, with birds progressively starting nesting before fields are sown. These nests are at high risk of destruction from incoming sowing operations. The results highlight the importance of considering human adaptation responses, in addition to those of wildlife, for implementing species conservation in managed landscapes under climate change.

Environmental Impact and Relative Invasiveness of Free-Roaming Domestic Carnivores-a North American Survey of Governmental Agencies.

Simple SummaryThis paper reports on a survey that explores the impact of three non-native domestic carnivores—dogs, cats, and ferrets—on the native wildlife of the United States (US) and Canada. Government agencies were asked to document the number and frequency of sightings, and the degree of concern resulting from free-roaming animals on urban, suburban, rural, recreational areas, and wildlands in their jurisdictions. Results confirm the existence of free-roaming cats and dogs throughout North America, as well as their profound impact on native wildlife, with cats being the major offenders. Except for an occasional stray, free-roaming ferrets were “never” or “rarely seen”; no agency reported that ferrets caused environmental harm. This is the first study to compare the relative impact of free-roaming dogs, cats, and ferrets. It shows differences in how these three animals react to novel environments. For the US and Canada, free roaming cats and dogs meet the definition of an “invasive” species, whereas ferrets do not. However, the way we as a society view these animals, our attitudes and perceptions, may influence how governmental agencies manage and control them.A survey of the United States and Canadian governmental agencies investigated the environmental impact and relative invasiveness of free-roaming domestic non-native carnivores—dogs, cats, and ferrets. Agencies represented wildlife, fish, game, natural or environmental resources, parks and recreation, veterinary and human health, animal control, and agriculture. Respondents were asked to document the number and frequency of sightings of unconfined animals, evidence for environmental harm, and the resulting “degree of concern” in their respective jurisdictions. Results confirmed the existence of feral (breeding) cats and dogs, documenting high levels of concern regarding the impact of these animals on both continental and surrounding insular habitats. Except for occasional strays, no free-roaming or feral ferrets were reported; nor were there reports of ferrets impacting native wildlife, including ground-nesting birds, or sensitive species. This is the first study to report the relative impact of free-roaming domestic carnivores. Dogs and cats meet the current definition of “invasive” species, whereas ferrets do not. Differences in how each species impacts the North American environment highlights the complex interaction between non-native species and their environment. Public attitudes and perceptions regarding these species may be a factor in their control and agency management priorities.