Detailed monitoring of a small but recovering population reveals sublethal effects of disease and unexpected interactions with supplemental feeding.

Infectious diseases are widely recognized to have substantial impact on wildlife populations. These impacts are sometimes exacerbated in small endangered populations, and therefore, the success of conservation reintroductions to aid the recovery of such species can be seriously threatened by outbreaks of infectious disease. Intensive management strategies associated with conservation reintroductions can further compound these negative effects in such populations. Exploring the sublethal effects of disease outbreaks among natural populations is challenging and requires longitudinal, individual life-history data on patterns of reproductive success and other indicators of individual fitness. Long-term monitoring data concerning detailed reproductive information of the reintroduced Mauritius parakeet (Psittacula echo) population collected before, during and after a disease outbreak was investigated. Deleterious effects of an outbreak of beak and feather disease virus (BFDV) were revealed on hatch success, but these effects were remarkably short-lived and disproportionately associated with breeding pairs which took supplemental food. Individual BFDV infection status was not predicted by any genetic, environmental or conservation management factors and was not associated with any of our measures of immune function, perhaps suggesting immunological impairment. Experimental immunostimulation using the PHA (phytohaemagglutinin assay) challenge technique did, however, provoke a significant cellular immune response. We illustrate the resilience of this bottlenecked and once critically endangered, island-endemic species to an epidemic outbreak of BFDV and highlight the value of systematic monitoring in revealing inconspicuous but nonetheless substantial ecological interactions. Our study demonstrates that the emergence of such an infectious disease in a population ordinarily associated with increased susceptibility does not necessarily lead to deleterious impacts on population growth and that negative effects on reproductive fitness can be short-lived.

Seasonal fluctuation in the neuronal classes of parahippocampal area of P. krameri (Scopoli, 1769) and E. scolopaceus (Linnaeus, 1758).

Hippocampus in birds is a relatively narrow, curved strip of tissue that lies on the dorsomedial surface of telencephalon. It is widest dorsally at the junction with parahippocampal area, and it tapers with septum. Parahippocampal area (APH), the most prominent field of hippocampus is a long structure that lies at the most rostral level and continues upto caudal extent. It has been indicated by behavioral studies that hippocampus in birds plays an important role in process of learning, memory formation, food storage and spatial navigation. The present study enlightens some interesting fluctuations occurring in the neuronal classes of parahippocampal area of two seasonally breeding birds viz. P. krameri and E. scolopaceus in terms of dendritic thickness, spine density and spine morphology during breeding and non-breeding time period of birds. The Golgi-impregnated sections were used to study these fluctuations and it was noticed that there was a significant increase in dendritic thickness, spine density, spine length and spine head diameter during breeding as compared to non-breeding period. The results obtained were comparable in two different seasonally breeding birds, supporting the view that avian parahippocampal area shows neuroanatomical plasticity associated with breeding and non-breeding period because of variations in endocrinology.

Foot preferences in wild-living ring-necked parakeets (Psittacula krameri, Psittacidae).

Evidence for foot preferences has been reported in parrots and the majority of parrot species uses the left foot to hold and process food objects. Here we assessed the footedness of ring-necked parakeets (Psittacula krameri) in a wild-living non-native population in Heidelberg, Baden-Wurttemberg, Germany. Observations were made when parrots fed on catalpa trees Catalpa sp., with 20- to 50-cm-long fruits. Parakeets tend to bite off catalpa fruits with their beak, using one foot holding the fruit. Further, we established an experimental set-up (feeding location) and prepared pieces of apple in an adequate size to force parrots to handle the food with one foot. From 184 individuals feeding on the catalpa trees, 102 were recorded using the left foot and 82 the right foot. At the feeding location, 24 individuals were left-footed and 11 were right-footed. These observations suggest a foot preference in the ring-necked parakeet both on the population level and on the individual level.

Alien invasive birds.

A bird species is regarded as alien invasive if it has been introduced, intentionally or accidentally, to a location where it did not previously occur naturally, becomes capable of establishing a breeding population without further intervention by humans, spreads and becomes a pest affecting the environment, the local biodiversity, the economy and/or society, including human health. European Starling (Sturnus vulgaris), Common Myna (Acridotheres tristis) and Red-vented Bulbul (Pycnonotus cafer) have been included on the list of '100 of the World's Worst Invasive Alien Species', a subset of the Global Invasive Species Database. The 'Delivering Alien Invasive Species Inventories for Europe' project has selected Canada Goose (Branta canadensis), Ruddy Duck (Oxyura jamaicensis), Rose-ringed Parakeet (Psittacula krameri) and Sacred Ibis (Threskiornis aethiopicus) as among 100 of the worst invasive species in Europe. For each of these alien bird species, the geographic range (native and introduced range), the introduction pathway, the general impacts and the management methods are presented.

Reproductive success of rose-ringed parakeets Psittacula krameri in a captive UK population.

BACKGROUND: Rose-ringed parakeets Psittacula krameri (Scop.) have recently become established in several European countries, with potential for significant negative economic and ecological impacts. However, in northern Europe the potential for reproductive output is largely unknown. In 2005 the authors established a captive outdoor colony in north-east England and examined breeding success over 2 years. RESULTS: In 2006 (19 pairs, 15 clutches) the average first clutch size was 3.6 (+/-0.3) eggs. Six clutches were infertile, and overall the colony produced 1.4 (+/-0.5) fertile eggs per pair. Eleven pairs produced a second clutch following removal of the first; seven were infertile, and overall productivity was 0.7 (+/-0.4) fertile eggs per pair. Unsuccessful pairs were rearranged or replaced. In 2007, overall productivity was 2.5 (+/-0.4) and 1.8 (+/-0.4) fertile eggs per pair for the first and second attempts respectively. For pairs that remained unchanged through 2006-2007, productivity was consistent between years and breeding attempts. CONCLUSION: Where food and nest sites were not limiting, clutch sizes in north-east England were similar to those in the native range, and consistent between first and second attempts. This has implications for the future expansion and management of the species.

Testicular functions and serum titers of LH and testosterone in methyl parathion-fed roseringed parakeets.

Adult male roseringed parakeets were fed concentrations (0, 10 or 20 microg/100g body wt./day) of methyl parathion (MP) for 5 or 10 days. There were four sampling periods for each treatment group. The first two sampling periods were after 5 or 10 days of daily dosing. In two other sampling periods, birds were given daily doses for 10 days, and sampling occurred at 5 or 10 days after the end of treatment. A significant dose- and duration-dependent reduction in the paired testicular weight, seminiferous tubular diameters, the number of tubules with healthy germ cells, plasma acetylcholinesterase (AChE) activity and plasma levels of luteinizing hormone (LH) and testosterone occurred in MP-fed birds. The inhibitory influences of MP persisted till day-5 and followed by recovery from the gonado-suppressive effects of MP at day-10 after the end of last treatment for 10 days. These findings provide the first experimental evidence that MP-induced testicular dysfunctions in parakeets possibly results from an impaired activity of hypophysial-gonadal axis. Moreover, it is evident that the organophosphorous (OP)-induced changes in the avian testes are reversible.