So near and yet so far: Harmonic radar reveals reduced homing ability of nosema infected honeybees

Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed

So near and yet so far: Harmonic radar reveals reduced homing ability of nosema infected honeybees

Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed

Exposure of bald eagle nestlings to contaminants on National Park Service lands within the Chesapeake Bay

We examined breeding performance (N=921) and nestling exposure (N=25 nests) to heavy metals (cadmium, lead, mercury), polychlorinated biphenyls (PCBs - 91 congeners) and organochlorine pesticides (OCPs - 11 compounds) for bald eagles nesting on National Park Service (NPS) and associated lands within the Chesapeake Bay (2016-2018). Nesting pairs on NPS lands were consistently more successful and had higher reproductive rates compared to other pairs along the James/York River study area but these differences were not statistically significant. Mean reproductive rates were above the level believed to be required for population maintenance for all areas examined. Blood concentrations of heavy metals were generally low and varied between metals examined. Cadmium did not exceed the level-of-detection (LOD) for any sample. Detection frequencies for Lead and Mercury were 86 and 100% respectively. Lead concentrations (range = 0.21-0.88, geometric mean = 0.49 ?g/g ww) were low and no sample exceeded the level (?g/dL) believed to represent background for raptors. Blood concentrations (range = 0.106-0.903, geometric mean = 0.335 ?g/g ww) of mercury were toward the lower to middle range of values reported from other studies of nestlings. Broods reared around lakes or tidal-fresh reaches had higher concentrations than broods reared around high-saline waters. No samples approached the general threshold (\u3e3.0 ?g/g ww) believed to result in possible reproductive impacts. Total PCB concentrations estimated during this study (range = 1.35-23.51, geometric mean = 6.34 ng/g ww) were on the low end of values reported from other regions. A cluster of the highest values were found within the lower James River. However, the highest values represented approximately 10% of the threshold (190 ng/g ww) suggested for reproductive impairment and 50% of the threshold (36 µg/kg) suggested for no-observed-adverse-effect-level (NOEL). Total OCP concentrations (range = 0.87-8.78, geometric mean = 2.68 ng/g ww) were lower than those reported from most other populations. p,p\u27-DDE was the most widespread pesticide compound and accounted for 93% of the total OCP values. Concentrations of p,p\u27-DDE (range = 0.6-8.78, geometric mean of 2.41 ng/g ww) were all below the level suggested for reproductive impairment (28 ng/g ww) and below the NOEL (11.4 ng/g ww) for productivity. Total concentrations of PCBs and OCPs were positively correlated (r=0.62,

Investigation of Red-cockaded Woodpeckers in Virginia: Year 2019 Report

The Virginia population of red-cockaded woodpeckers is the northernmost throughout the species range and has been in eminent danger of extinction for more than 30 years. The Piney Grove Preserve represents a nucleus for recovery in the state and the focus of a multi-organizational partnership designed to increase the population to a sustainable level. The partnership has executed a program of aggressive habitat management, cavity-tree management and woodpecker population monitoring and management that has resulted in a quadrupling of the breeding population since the early 2000s. During the 2019 breeding season, Piney Grove Preserve supported 15 potential breeding groups (including one in the Big Woods) that produced 27 fledglings. All groups made breeding attempts, including the cluster in Big Woods for the first time, though three clusters (10, 17, and 18) failed to produce fledglings. The population as a whole had a reproductive rate of 1.8±0.35 (mean±SE) young/breeding group. The 13 groups that made breeding attempts had a success rate of 80% (12 of 15). Fledging rate for the 12 productive pairs was 2.3±0.32. Of the 61 eggs followed in 2019, 40 (65.6%) hatched, 21 (55.7%) survived to banding age, and 28 (45.9%) fledged. Birds that fledged included 18 females, 9 males, and 1 of unknown sex. Fifteen of these birds were retained and detected during the winter count and two (both male) were translocated to Great Dismal Swamp, NWR on 17 October. During the calendar year of 2019, 101 individual red-cockaded woodpeckers were identified within Piney Grove preserve including 72 birds that were hatched at Piney Grove during previous years and 29 nestlings that fledged during the 2019 breeding season. Forty-one birds (41%) were in their fourth year or more and ten birds (10%) were at least in their tenth year. One bird was fifteen years old (sixteenth calendar year). Moving into the breeding season there were 65 birds were identified within Piney Grove Preserve distributed among 15 clusters. This ties 2017 as the highest number of adults that Piney Grove has ever carried into the breeding season. The number of birds per cluster varied from two to seven with a mean of 4.33±0.45 (mean+SE). Seventy-seven birds were detected during the 2018 winter survey. This represents a 5% increase over the winter of 2018 and a 13% increase over the winter of 2017. Birds present include 15 of the 29 birds fledged in 2017 and 62 adult birds hatched in previous years. Group size in winter ranged from two to nine birds and averaged 5.13 ± 0.56 (mean±SE) birds per group

Investigation of Red-cockaded Woodpeckers in Virginia: Year 2020 Report

The Virginia population of red-cockaded woodpeckers is the northernmost throughout the species range and has been in eminent danger of extinction for more than 30 years. The Piney Grove Preserve represents a nucleus for recovery in the state and the focus of a multi-organizational partnership designed to increase the population to a sustainable level. The partnership has executed a program of aggressive habitat management, cavity-tree management and woodpecker population monitoring and management that has resulted in a quadrupling of the breeding population since the early 2000s. During the 2020 breeding season, Piney Grove Preserve supported 15 potential breeding groups (including one in the Big Woods) that produced 30 fledglings. All groups made breeding attempts, including the cluster in Big Woods for the second time, though two clusters (cluster 8 and Big Woods) failed to produce fledglings. The population as a whole had a reproductive rate of 2.0 ±0.31 (mean±SE) young/breeding group. The 15 groups that made breeding attempts had a success rate of 86.7% (13 of 15). Fledging rate for the 13 productive pairs was 2.3±0.64. Of the 63 eggs followed in 2020, 34 (54.0%) hatched, 34 (54.0%) survived to banding age, and 30 (47.6%) fledged. Birds that fledged included 21 females and 9 males. Seventeen of these birds were retained and detected during the winter count and four (two males and two females) were translocated to Great Dismal Swamp, NWR on 07–08 October. During the calendar year of 2020, 102 individual red-cockaded woodpeckers were identified within Piney Grove Preserve including 72 birds that were hatched at Piney Grove during previous years and 30 nestlings that fledged during the 2020 breeding season. Thirty-one birds (41%) were in their fourth year or more and nine birds (10%) were at least in their tenth year. One bird was 16 years old (17th calendar year). Moving into the breeding season there were 67 birds identified within Piney Grove Preserve distributed among 15 clusters. This is the most birds Piney Grove has carried heading into the breeding season (two more than in 2017 and 2019). The number of birds per cluster varied from two to seven with a mean of 4.33±0.45 (mean+SE). Eighty birds were detected during the 2020 winter survey. This represents a 5% increase over the winter of 2019 and a 13% increase over the winter of 2018. Birds present during the winter survey included 17 of the 30 birds fledged in 2020 and 63 adult birds hatched in previous years. Group size in winter ranged from two to nine birds and averaged 5.04 ± 0.50 (mean±SE) birds per group

Assessment of Black Rail Status in Georgia, Breeding Season 2017 and 2018 Summaries

The Black Rail (Laterallus jamaicensis) is the most secretive and least understood marsh bird in North America with the Eastern Black Rail (L. j. jamaicensis), one of two subspecies that occur here, listed as endangered in six states along the Atlantic Coast and proposed for federal listing under the Endangered Species Act (USFWS–R4–ES–2018–0057, 2018). Black Rails require dense vegetation for cover during all stages of their life cycle. They require wetlands with minimal water coverage during the breeding season. Historic population size for the Eastern subspecies was likely in the tens of thousands (25,000 to 100,000; Delaney and Scott 2002) but is now believed to be in the hundreds to low thousands. Eastern Black Rails breed within three geographic areas within North America including the Atlantic Coast, the Gulf Coast, and the Midwest. The Atlantic Coast has generally been considered to support the largest breeding population throughout the range with pairs mostly confined to the highest elevations within tidal salt marshes. Breeding range along the Atlantic Coast has contracted south more than 450 kilometers and the population is estimated to be declining by 9% annually (Watts 2016). The primary driver of declines over the past three decades is believed to be sea-level rise and associated tidal inundation during the nesting season. Georgia is noticeably missing from most of the early descriptions of Eastern Black Rail distribution (e.g. Allen 1900, Bent 1926, Forbush 1929). Early authors describing Eastern Black Rail status in the state (Burleigh 1938, Greene et al. 1945, Burleigh 1958) indicate that the species was perhaps more common and widespread in previous decades. As in all states within the breeding range, the lack of status and distribution information is certainly facilitated by their secretive habits, but in Georgia this is also likely reflected in an extremely low population size, a lack of overlap between Black Rails and bird watchers, or both. Scattered historic occurrences along the outer coast suggested a presence of a potential breeding population (Sykes 2010). The Eastern Black Rail ranks as a species of high conservation concern (GA DNR Wildlife Action Plan 2015) and breeding season surveys ranked as one of the highest conservation action priorities within the plan. The 2016 population estimate for the state (based on available habitat) was 10 to 40 pairs though the uncertainty in this estimate was very high (Watts 2016). The only definitive breeding record in the state comes from Greene County (Sykes 2010), and this site has been the most consistently documented breeding area throughout the state in the past 25 years (Watts 2016). During the 2017 field season, 409 coastal points were surveyed, and during the 2018 field season 206 points were surveyed. All points surveyed in 2017 were along the outer coast in tidal or impounded wetlands. During the 2018 survey, 141 inland points and 65 coastal points were surveyed. Three rounds of surveys were conducted between 18 April and 17 July 2017 and between 1 May and 15 July 2018. All points were surveyed three times unless there were access issues during one of the survey rounds. A total of 1,827 individual play-back surveys were conducted, 1,213 in 2017, and 614 in 2018. We detected no Black Rails during either season