Preface. Section 1: Introduction to the Study of Birds in Urban Environments. 1. A historical perspective on urban bird research: trends, terms, and approaches J.M. Marzluff, R. Bowman, R. Donnelly. 2. Worldwide urbanization and its effects on birds J.M. Marzluff. 3. Synanthropic birds of North America R.F. Johnston. 4. Human perception and appreciation of birds: A motivation for wildlife conservation in urban environments of France P. Clergeau, G. Mennechez, A. Sauvage, A. Lemoine. 5. Quantifying the urban gradient: linking urban planning and ecology M. Alberti, E. Botsford, A. Cohen. 6. Urbanization, avian communities, and landscape ecology J.R. Miller, J.M. Fraterrigo, N. Thompson Hobbs, D.M. Theobald, J.A. Wiens. 7. The importance of multi-scale analyses in avian habitat selection studies in urban environments M. Hostetler. Section 2: Processes Affecting Birds in Urban Environments. 8. Urban birds: Population, community, and landscape approaches D. Bolger. 9. Interactions among non-native plants and birds S. Hayden Reichard, L. Chalker-Scott, S. Buchanan. 10. Urban sprawl and juniper encroachment effects on abundance of wintering passerines in Oklahoma B.R. Coppedge, D.M. Engle, S.D. Fuhlendorf, R.E. Masters, M.S. Gregory. 11. Nest predator abundance and urbanization D.G. Haskell, A.M. Knupp, M.C. Schneider. 12. Bird tolerance to human disturbance in urban parks of Madrid (Spain): Management implications E. Fernandez-Juricic, M.D. Jiminez, E. Lucas. 13. Settlement of breeding European Starlings in urban areas: importance oflawns vs. anthropogenic wastes G. Mennechez, P. Clergeau. 14. Variation in the timing of breeding between suburban and wildland Florida Scrub-Jays: Do physiologic measures reflect different environments? S.J. Schoech, R. Bowman. Section 3: Bird Populations in Urban Environments. 15. The ecology of Western Gulls in habitats varying in degree of urban influence R. Pierotti, C. Annett. 16. Causes and consequences of expanding American Crow populations J.M. Marzluff, K.J. McGowan, R. Donnelly, R.L. Knight. 17. Demographic and behavioral comparisons of suburban and rural American Crows K. McGowan. 18. Nest success and the timing of nest failure of Florida Scrub-Jays in suburban and wildland habitats R. Bowman, G.E. Woolfenden. 19. Synurbanization of the Magpie in the Palearctic L. Jerzak. 20. Maccaw abundance in relation to human population density in the western Amazon basin D.M. Brooks, A.J. Begazo. 21. Waterbird production in an urban center in Alaska M.R. North. Section 4: Bird Communities in Urban Environments. 22. Creating a homogeneous avifauna R.B. Blair. 23. Avian community characteristics of urban greenspaces in St. Louis, Missouri J.M. Azerrad, C.H. Nilon. 24. The importance of the Chicago region and the 'Chicago Wilderness' initiative for avian conservation J.D. Brawn, D.F. Stotz. 25. Do temporal trends in Christmas Bird Counts reflect the spatial trends of urbanization in southwestern Ohio? N.A. Crosby, R.B. Blair. 26. Survey techniques and habitat relationships of breeding birds in residential areas of Toronto, Canad

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Avian ecology and conservation in an urbanizing world

The genus Castor comprises two species: the Eurasian beaver Castor fibre , and the North American beaver Castor canadensis . Both species suffered from overexploitation, but have seen a revival since the 1920s due to increased protection and reintroduction programmes. Increases in the populations and distributions of species that are able to modify ecosystems have generated much scientific interest. Here we review the available literature concerning the possible ecological impact of beaver species in the Old and New World. 2. Beavers, being ecosystem engineers, are among the few species besides humans that can significantly change the geomorphology, and consequently the hydrological characteristics and biotic properties of the landscape. In so doing, beavers increase heterogeneity, and habitat and species diversity at the landscape scale. Beaver foraging also has a considerable impact on the course of ecological succession, species composition and structure of plant commu- nities, making them a good example of ecologically dominant species (e.g. keystone species). 3. Nevertheless, the strength of beavers' impact varies from site to site, depending on the geographical location, relief and the impounded habitat type. Consequently, they may not be significant controlling agents of the ecosystem in all parts of their distribution, but have strong interactions only under certain circumstances. We suggest that beavers can create important management opportunities in the Holarctic, and this review will help land man- agers determine the likely outcome of beaver activity.

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Ecological impact of beavers Castor fiber and Castor canadensis and their ability to modify ecosystems

On 16 November 2005 a water sample was taken from an urban stream in a metropolitan area in the southern United States and tested for the presence of E. coli. Although water samples from this and other streams in the metropolitan area frequently registered over 15,000 colonies/100 ml, this particular sample is unique in that it registered a reading of 70,000 colonies/100 ml, 350 per cent greater than the 200 colonies/100 ml—the Environment Protection Agency’s standard for streams. The fetid fl oodwaters in New Orleans from Hurricane Katrina, which had a contamination level of 10,000 colonies/100 ml and attracted considerable public attention, were cleaner than this stream at the time of sampling. Although a number of factors can contribute to this high reading, the stream consistently failed to meet water quality standards throughout the year. In addition, children from the local neighbourhood often played in the stream. Yet, presentations on water quality issues and potential health hazards did not raise any concerns among the citizenry, news outlets, and policy-makers. Obviously, there appears to be a disconnection between social and ecological systems as refl ected by the lack of concern by residents, natural resource managers, and decision-makers to the degraded stream conditions. This disconnection suggests the following question: How are social and ecological systems linked in urban landscapes and how does one begin to examine that linkage? In this chapter, we explore the linkage between the ecological and social systems of urban landscapes. First, we examine two metrics—sense of place and land cover—that have been used to integrate social and ecological systems. Second, we examine how system models have been used to link ecological systems with social systems. Third, we introduce the concept of complex adaptive systems (Gunderson & Holling 2002), as it may apply to urban landscapes, and fi nally we present a socio-ecological model ( Morse 2007 ), based on complex adaptive systems and structuration theory ( Stones 2005 ), as a means to link social systems with ecological systems.

/pdf/linking-social-and-ecological-systems-460fxm21cp.pdf

Linking social and ecological systems

Summary Scent-marking is a ubiquitous form of olfactory signaling in male mammals and both territorial males in resource-defense mating systems and dominant males in dominance mating systems scent-mark. A large body of evidence suggests a link between scent-marking by male mammals and intrasexual competition. Resource holders appear to mark to help establish and maintain their status. They may do this because scent marks allow potential opponents to assess the status or RHP of the signaler. Nonresource holding competitors benefit because they can adjust the level of escalation in relation to potential costs and benefits and avoid risky contests. Resource holders benefit through reduced costs because many nonresource holders withdraw to avoid escalated contests. Three basic mechanisms allow receivers to make decisions after detecting scent marks. Receivers may (1) detect intrinsic properties of scent marks (e.g., concentrations of androgen-dependent volatiles), (2) remember past contests and the odor of each individual involved and associate these with the odor of scent marks, and (3) remember the smell of marks recently encountered and match this smell with potential opponents that they meet subsequently. It is now known that all of these mechanisms are used, sometimes within one species (e.g., mice) and we argue that the mechanisms are used conditionally, depending on information available and potential costs and benefits to receivers. Game theoretical analysis has recently shown how territorial intruders may switch from using intrinsic properties of marks to scent-matching when making decision about whether to remain in a territory. Scent-marking may be a uniquely cheat-proof signal of status because males must be able to defend their territory or dominance status over the time taken to mark it. A pattern of marks is thus a signal of status that has been tested in intrasexual competition. It also seems likely that marks are intrinsically costly both in energetic terms and by increasing predation risk. Mice can detect whether urine is from a parasitized or nonparasitized individual and these odors could potentially signal immunocompetence if mediated by variation at the MHC region of the genome. This remains to be tested. It is known that mice can detect relatedness via urine volatiles mediated by the MHC and it has been predicted that males should modify their competitive behavior in the light of this information. Again this remains to be tested. Information about disease status and genetic relatedness does not explain why males maintain patterns of scent marks. Most, perhaps all, territories are scent-marked. This may be because most intruders are of lower RHP than resource holders and these males should usually withdraw after assessing the resource holder by its scent marks. The costs of defending a territory may thus be substantially reduced. The obligate link between scent-marking and territoriality suggests that resource-defense polygyny in mammals may not be economically viable without this reduction in the costs of area defense. A little information is available to show that females use information from patterns of scent marks and a great deal of information shows that they use intrinsic information. It is not known whether males signal to females to enable mate choice or if females eavesdrop on signals sent between male competitors. Most known responses are to male urine by female rodents. For example, females show physiological (priming) responses to male odors (e.g., advancing and synchronizing estrus, inducing abortion). Other research has identified factors responsible for female mate preferences in choice tests. For example, the dominance status of the signaling male is a predictor of female interest and such studies have identified androgen-dependent volatiles responsible for the response. More recently, females have been shown to use odor mediated by the MHC locus to choose mates in relation to their genetic relatedness and to use odor to distinguish healthy and diseased mates. Most of these studies have been on mice and most use male urine, but the effect of patterns of urine scent marks has not been investigated. The only studies that explicitly use scent marks are those showing that females match the odor of potential mates with marks previously found in the environment to select mates. Future research should aim to clarify how information about the quality of potential mates is transmitted and how females trade-off such information against genetic relatedness.

Scent-marking by male mammals: Cheat-proof signals to competitors and mates

The control of predators for nature conservation purposes is becoming an increasingly important issue. The growing populations of predator species in some areas and the introduction of predators in other areas have led to concerns about their impact on vulnerable bird species and to the implementation of preda- tor control in some cases. This is set against a background of increasingly fragmented semi-natural habitats and declining populations for many species. To assess the efficiency of predator removal as a conservation measure, the results of 20 published studies of predator removal programs were meta-analyzed. Removing predators had a large, positive effect on hatching success of the target bird species, with removal areas show- ing higher hatching success, on average, than 75% of the control areas. Similarly, predator removal increased significantly post-breeding population sizes (i.e. autumn densities) of the target bird species. The effect ofpred- ator removal on breeding population sizes was not significant, however, with studies differing widely in their reported effects. We conclude that predator removal often fulfills the goal of game management, which is to enhance harvestable post-breeding populations, but that it is much less consistent in achieving the usual aim of conservation managers, which is to maintain and, where appropriate, increase bird breeding population sizes. This may be due to inherent characteristics of avian population regulation, but also to ineffective pred- ator removal and inadequate subsequent monitoring of the prey populations.

https://www.jstor.org/stable/info/2387614

The Effectiveness of Removing Predators to Protect Bird Populations

Beaver (Castor spp.) normally scent-mark by depositing castoreum and/or anal gland secretion on scent mounds close to the water's edge. The aim of this study was to investigate the hypothesis that the Eurasian beaver (C. fiber) scent-marks as a means of territory defense. Scent-marking behavior was studied during an entire year (April 1, 1995–March 31, 1996) in seven adjacent territories along 9.2 km of the BΦ River in Telemark County, Norway. The number and location of fresh scent marks were recorded biweekly. The main results showed that: (1) the number of scent marks in territories was significantly higher in spring, when dispersal of subadults normally occurs than during the rest of the year; (2) the number of scent marks was clumped near territorial borders; and (3) the number of scent marks was significantly greater upstream than downstream of the lodge.

Scent-marking in the Eurasian beaver (Castor fiber) as a means of territory defense

L'elimination de Corvus corone, C. corax et Pica pica dans une zone experimentale de l'ile de Karlsoy, Norvege n'abaisse pratiquement pas la mortalite de Lagopus lagopus et de Lyrurus tetrix

Effect of corvid removal on reproduction of willow ptarmigan and black grouse

Seven North American beavers Castor canadensis (Cc) were introduced into Finland in 1937 to supplement an ongoing reintroduction of the nearly extinct Eurasian beaver C. fiber (Cf). At that time, many zoologists recognised only one species. However, in 1973, chromosome counts (Cf = 48, Cc = 40) acknowledged two species, and Cc became an invasive alien. Recently, expanding populations of both species have converged on two fronts in Finland and northwestern Russia. According to Gause's competitive exclusion principle, two species with identical niches cannot coexist indefinitely . The imminent question is whether coexistence or competitive exclusion will ultimately result, with the possible regional extirpation or eventual extinction of Cf. We reviewed published cases of interspecies contact and compared their life history, ecology and behaviour. The few published incidences of contact were inconclusive with respect to competitive advantage. Body size is similar, but Cc litter size is slightly greater. Only...

https://bioone.org/journals/wildlife-biology/volume-18/issue-4/12-007/Invasive-North-American-beaver-Castor-canadensis-in-Eurasia--a/10.2981/12-007.pdf

Invasive North American beaver Castor canadensis in Eurasia: a review of potential consequences and a strategy for eradication

Accurate determination of age is essential for many ecological studies. Though counts of cementum annuli zones in teeth usually provide the most accurate measure of age in mammals, the technique is technically demanding, highly invasive and expensive. Consequently, ecologists and archaeologists are constantly seeking alternative methods of accurate age determination. In this study, we correlated the age of Eurasian beaver (Castor fiber) with skull length and width, body length and mass, hind foot length, tail width and length and an index of tail size to determine if these measurements were accurate predictors of age. The relationships between all measurements and age were curvilinear, making them particularly unreliable for older age classes. Skull length and width were the best predictors of age, but only individuals ≤2 years could be assigned to their correct age class with a probability >50%. However, when allowing for an error of ±1 year, the success rate of both skull measurements increased to ≥60% for females up to 4 years of age and for males up to 3 years of age. We concluded that body measurements are unsuitable predictors of accurate individual age in beavers but that especially skull length and skull width may be useful if separation into age classes such as juvenile, subadult and adult is sufficient.

Howard Parker

Papers

Ecological impact of beavers Castor fiber and Castor canadensis and their ability to modify ecosystems

Scent-marking in the Eurasian beaver (Castor fiber) as a means of territory defense

Effect of corvid removal on reproduction of willow ptarmigan and black grouse

Invasive North American beaver Castor canadensis in Eurasia: a review of potential consequences and a strategy for eradication

Correlates of body measurements and age in Eurasian beaver from Norway