Potential Role of Avian Populations in the Epidemiology of Rickettsia spp. and Babesia spp.

Birds often are carriers of hard and/or soft ticks harboring pathogens of humans and veterinary concern. Migratory avian species, which cover long distance by their flight, may deeply influence the ticks’ distribution worldwide; in particular, they can introduce in a given geographic area new tick species and related tick-borne pathogens. Studies about the detection of tick-borne agents in birds are not numerous, whereas more attention has been turned to the presence of these microorganisms in ticks carried by birds. The present review focused on the role of avian populations in the epidemiology of rickettsioses and babesioses, which represent two severe problems for the health of humans and other mammals.

Complete Life Cycle of Trypanosoma thomasbancrofti, an Avian Trypanosome Transmitted by Culicine Mosquitoes

Avian trypanosomes are cosmopolitan and common protozoan parasites of birds; nevertheless, knowledge of their life cycles and vectors remains incomplete. Mosquitoes have been confirmed as vectors of Trypanosoma culicavium and suggested as vectors of T. thomasbancrofti; however, transmission has been experimentally confirmed only for the former species. This study aims to confirm the experimental transmission of T. thomasbancrofti to birds and its localization in vectors. Culex pipiens were fed on blood using four strains of T. thomasbancrofti, isolated from vectors and avian hosts; all strains established infections, and three of them were able to develop high infection rates in mosquitoes. The infection rate of the culicine isolates was 5–28% for CUL15 and 48–81% for CUL98, 67–92% for isolate OF19 from hippoboscid fly, while the avian isolate PAS343 ranged between 48% and 92%, and heavy infections were detected in 90% of positive females. Contrary to T. culicavium, trypanosomes were localized in the hindgut, where they formed rosettes with the occurrence of free epimastigotes in the hindgut and midgut during late infections. Parasites occurred in urine droplets produced during mosquito prediuresis. Transmission to birds was achieved by the ingestion of mosquito guts containing trypanosomes and via the conjunctiva. Bird infection was proven by blood cultivation and xenodiagnosis; mature infections were present in the dissected guts of 24–26% of mosquitoes fed on infected birds. The prevalence of T. thomasbancrofti in vectors in nature and in avian populations is discussed in this paper. This study confirms the vectorial capacity of culicine mosquitoes for T. thomasbancrofti, a trypanosome related to T. avium, and suggests that prediuresis might be an effective mode of trypanosome transmission.

Impact of Vegetation Cover Structure on Birds' Community at Tianfu National Wetland Park in Jiangsu Kunshan, China

Background: Vegetation cover has an essential role in wetland habitats in controlling avian populations throughout the world. The vegetation cover structure in grassland systems varies dramatically among seasons on the same sites. Variation in vegetation cover-abundance richness and diversity has been studied through one hundred forty-seven quadrate samples during summer and autumn, 2019, winter, and spring 2020. Avian species richness and diversity were recorded during the same period. Results: The correlation analysis results confirmed that: (1) there was no apparent seasonal difference in the abundance of vegetation cover while avian abundance was statistically different. (2) Plant abundance in summer was positively correlated with the number of avian, while in autumn it was negatively correlated. Plant and avian abundance at the genus level showed a positive correlation while maintaining a negative correlation at the species level (p < 0.05). However, during summer and autumn, a strong linear relationship exists between vegetation coverage and avian. The Shannon diversity index and Simpson diversity index have a positive linear relationship between vegetation coverage and avian families and genera. Conclusions: We conclude that vegetation coverage richness significantly impact avian communities. We suggest further research into the relationship between other biological communities and farming practices in the wetlands.

Impact of Vegetation Cover Structure on Birds' Community at Tianfu National Wetland Park in Jiangsu Kunshan, China

Vegetation cover has an essential role in wetland habitats in controlling avian populations throughout the world. The vegetation cover structure in grassland systems varies dramatically among seasons on the same sites. Variation in vegetation cover-abundance richness and diversity has been studied through one hundred forty-seven quadrate samples during summer and autumn, 2019, winter, and spring 2020. Avian spe cies richness and diversity were recorded during the same period. Meanwhile, correlation analysis results confirmed that: (1) there was no apparent seasonal difference in the abundance of vegetation cover while avian abundance was statistically different. (2) Plant abundance in summer was positively correlated with the number of avian, while in autumn it was negatively correlated. Plant and avian abundance at the genus level showed a positive correlation while maintaining a negative correlation at the speci es level (p < 0.05). However, during summer and autumn, a strong linear relationship exists between vegetation coverage and avian. The Shannon diversity index and Simpson diversity index have a positive linear relationship between vegetation coverage and a vian families and genera. Therefore, we conclude that vegetation coverage and richness significantly impact avian communities. We suggest further research into the relationship between other biological communities and farming practices in the wetlands.

Impact of Vegetation Cover Structure on Birds' Community at Tianfu National Wetland Park in Jiangsu Kunshan, China

Vegetation cover has an essential role in wetland habitats in controlling avian populations throughout the world. The vegetation cover structure in grassland systems varies dramatically among seasons on the same sites. Variation in vegetation cover-abundance richness and diversity has been studied through one hundred forty-seven quadrate samples during summer and autumn, 2019, winter, and spring 2020. Avian species richness and diversity were recorded during the same period. Meanwhile, correlation analysis results confirmed that: (1) there was no apparent seasonal difference in the abundance of vegetation cover while avian abundance was statistically different. (2) Plant abundance in summer was positively correlated with the number of avian, while in autumn it was negatively correlated. Plant and avian abundance at the genus level showed a positive correlation while maintaining a negative correlation at the species level (p < 0.05). However, during summer and autumn, a strong linear relationship exists between vegetation coverage and avian. The Shannon diversity index and Simpson diversity index have a positive linear relationship between vegetation coverage and avian families and genera. Therefore, we conclude that vegetation coverage and richness significantly impact avian communities. We suggest further research into the relationship between other biological communities and farming practices in the wetlands

Reconstructing Long-Term Changes in Avian Populations Using Lake Sediments: Opening a Window Onto the Past

The lack of long-term monitoring data for many wildlife populations is a limiting factor in establishing meaningful and achievable conservation goals. Even for well-monitored species, time series are often very short relative to the timescales required to understand a population’s baseline conditions before the contemporary period of increased human impacts. To fill in this critical information gap, techniques have been developed to use sedimentary archives to provide insights into long-term population dynamics over timescales of decades to millennia. Lake and pond sediments receiving animal inputs (e.g., feces, feathers) typically preserve a record of ecological and environmental information that reflects past changes in population size and dynamics. With a focus on bird-related studies, we review the development and use of several paleolimnological proxies to reconstruct past colony sizes, including trace metals, isotopes, lipid biomolecules, diatoms, pollen and non-pollen palynomorphs, invertebrate sub-fossils, pigments, and others. We summarize how animal-influenced sediments, cored from around the world, have been successfully used in addressing some of the most challenging questions in conservation biology, namely: How dynamic are populations on long-term timescales? How may populations respond to climate change? How have populations responded to human intrusion? Finally, we conclude with an assessment of the current state of the field, challenges to overcome, and future potential for research.

A Review of Chlamydial Infections in Wild Birds

The Chlamydia are a globally distributed genus of bacteria that can infect and cause disease in a range of hosts. Birds are the primary host for multiple chlamydial species. The most well-known of these is Chlamydia psittaci, a zoonotic bacterium that has been identified in a range of wild and domesticated birds. Wild birds are often proposed as a reservoir of Chlamydia psittaci and potentially other chlamydial species. The aim of this review is to present the current knowledge of chlamydial infections in wild avian populations. We focus on C. psittaci but also consider other Chlamydiaceae and Chlamydia-related bacteria that have been identified in wild birds. We summarise the diversity, host range, and clinical signs of infection in wild birds and consider the potential implications of these infections for zoonotic transmission and avian conservation. Chlamydial bacteria have been found in more than 70 species of wild birds, with the greatest chlamydial diversity identified in Europe. The Corvidae and Accipitridae families are emerging as significant chlamydial hosts, in addition to established wild hosts such as the Columbidae. Clarifying the effects of these bacteria on avian host fitness and the zoonotic potential of emerging Chlamydiales will help us to understand the implications of these infections for avian and human health.

Multi-scale temporal variation in bird-window collisions in the central United States

Expansion of urbanization and infrastructure associated with human activities has numerous impacts on wildlife including causing wildlife-structure collisions. Collisions with building windows represent a top bird mortality source, but a lack of research into timing of these collisions hampers efforts to predict them and mitigate effects on avian populations. In Stillwater, Oklahoma, USA, we investigated patterns of bird-window collisions at multiple temporal scales, from within-day to monthly and seasonal variation. We found that collisions peaked during overnight and early morning hours, a pattern that was consistent across seasons. Further, temporal variation in fatal collisions was explained by an interaction between season and avian residency status. This interaction illustrated the expected pattern that more migrant individuals than residents collided in fall, but we also documented unexpected patterns. For example, the highest monthly total of collisions occurred in spring migration during May. We also found similarly high numbers of resident and migrant collisions in spring, and a roughly similar amount of migrant mortality in spring and fall migration. These findings, which provide unprecedented quantitative information regarding temporal variation in bird-window collisions, have important implications for understanding mechanisms by which birds collide and improving timing of measures to reduce this major bird mortality source.