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Recent Research

Braddock Bay Bird Observatory  supports research conducted by our own internal staff, as well as by professors and graduate students at various universities.  Here is a list of some projects recently carried out at BBBO.

An assessment of the refueling performance of migrating Catharus thrushes during autumn stopover at Braddock Bay Bird Observatory in relation to fruit quality

Researcher:  Dr. Susan Smith Pagano, Rochester Institute of Technology

During autumn, wild fruits are widely consumed by migrating songbirds and may represent an important source of nutrients for refueling birds during brief migration stopovers. However, we know very little about how fattening rates of birds at stopover sites are affected by fruit consumption and whether high-quality (energy dense, high-fat) fruits can enhance refueling performance and body condition of migrating birds.  Previous research in the Nutritional Ecology lab at RIT suggests that native fruits (e.g. dogwoods, Arrowwood Viburnum) have higher fat and energy content than the fruits of invasive shrubs (e.g. Bush Honeysuckles, Common Buckthorn, Multiflora Rose). In addition, birds are likely to experience tremendous oxidative stress during the migratory period, and it is possible that the polyphenolic compounds present in wild fruits may provide a dietary source of antioxidant protection. This project will quantify refueling rates and nutritional status of highly frugivorous Catharus thrushes during autumn, when fruit is abundant at BBBO, and spring, when fruit is unavailable as a food resource.  In doing so, we aim to link variation in the physiological condition of birds with interannual variation in fruit quality at BBBO, and show that the incorporation of fruit in the diet of birds may provide physiological benefits in the fall when fruits represent their main food resource.

Plasma metabolite profiling offers a useful means to evaluate energy metabolism and physiological condition of migrating birds because certain metabolites indicate fat deposition and mass gain (plasma triglyceride), fat catabolism and mass loss (plasma ketone bodies), and dietary protein intake (plasma uric acid) over the previous several hours.  We will measure the concentration of these metabolites in the plasma of migrating thrushes to inform us about instantaneous refueling rates.  We will also measure plasma total antioxidant capacity of these birds, which can then be related to the total phenol content of consumed fruits as a potential source of antioxidant protection.  Results of this project will provide important insight into why songbirds consume specific fruits during migration stopovers and the physiological benefits of seasonal frugivory for migrating birds.

The relationship of energetic condition and migratory orientation at a fall stopover site located near an ecological barrier

Researcher:  Jennalee Holzschuh, Masters Candidate at SUNY Brockport under the guidance of Mark Deutschlander of Hobart and William Smith Colleges

Long and short-distance migration is an energy-intensive behavior undertaken in both spring and fall by millions of songbirds, in order to reach distant breeding and wintering grounds.  When faced with large ecological barriers (such as bodies of water or deserts), migrants in poor energetic condition alter their migratory trajectory in order to replenish energy reserves in stopover habitats prior to crossing the barrier.  Understanding how songbirds utilize stopover habitat has important implications for both management and conservation, because a bird’s energetic condition may affect its probability of survival during migration, and its reproductive success once it arrives on the breeding grounds.

My study examines the relationship between energetic condition and flight trajectories of White-throated Sparrows (Zonotrichia albicollis) arriving at Braddock Bay Bird Observatory on the south shore of Lake Ontario. I am comparing the orientation (i.e., direction) of both fat birds and lean birds.  I expect fat birds to orient in a seasonally appropriate direction (e.g., south in the fall) because they have enough stored energy to continue migration; conversely, I expect lean birds to orient either along the lakeshore or away from the lakeshore because they need to refuel before continuing migration. To determine a bird’s orientation, I place it in an Erlenmeyer-type funnel and video record its movement for one hour.  I use a computer program to analyze each video and determine overall orientation for each bird (based on hops). (Fall 2013 – Spring 2014)

Uncovering the Mysteries of Songbird Mating Patterns

Researchers:  Dr. Sara Kaiser <sak275@cornell.edu> and Dr. Scott Taylor <sat235@cornell.edu>, Cornell Lab of Ornithology

Black-throated Blue Warblers (Setophaga caerulescens) are small, territorial, insect-eating songbirds that breed in eastern North America and migrate to the Caribbean for the winter. Most males are “socially monogamous,” meaning they are mated to a single female. However, 10% of males are bigamous, with two females nesting on their territories, and up to 50% of Black-throated Blue Warbler (BTBW) nests have young sired by a male that is not the territory holder. We have been studying the mating system of these warblers in the hardwood forests of New Hampshire since 1995.

 Population monitoring of the migratory BTBW at the Hubbard Brook Experimental Forest is part of a long-term demographic study, part of which evaluates individual fitness by determining paternity using molecular resources. Thus far, microsatellite markers have been the marker of choice for determining paternity; however, these markers can be difficult to accurately score and their evolution is poorly understood. Single nucleotide polymorphisms (SNPs) present a more attractive marker for paternity studies given their ease of scoring and mutation patterns; however, no comprehensive comparison between the two marker types related to the number and variability of markers necessary for high paternity exclusion probability has been undertaken in birds.

To develop a set of SNPs for paternity analyses in BTBW for comparison to a long-term microsatellite dataset, we propose to assemble the BTBW transcriptome from which we will call SNPs to construct a SNPs-for-paternity assay. Transcriptome assembly and variant calling will utilize tissue samples from a single BTBW currently in the Cornell Museum of Vertebrates tissue collection along with blood samples from between 8 to 10 individuals from BBBO.  We will extract RNA from the collected blood and use alignment of these individuals to the assembled transcriptome to identify variants and score SNPs. This panel of SNPs will then be analyzed in a dataset from Hubbard Brook for which we have comparable microsatellite data to directly compare the efficacy of SNPs and microsatellites for avian paternity determination. This has not yet been rigorously done in birds. Additionally, this panel of SNPs will be used to evaluate population genetic differentiation between northern and southern breeding populations of BTBW, which show some morphological and behavioral differences. A comprehensive examination of population differentiation has not yet been carried out for this species and will provide valuable insight. (Spring 2014)

What’s Crawling On The Skin Of Our Fair Feathered Friends

 Researcher:  Jason Mayberry and Students at Canisius College

Birds are host to many ectoparasites such as lice, mites, ticks, and flies.  Among the fly parasites are the well-known blow flies, gnats, and mosquitoes.  My research is focused on a less well studied group of fly parasites comprising the family Hippoboscidae, the “Hippo Flies” which pester mammals as well as birds.  Hippo flies are part of a small clade of insects that possess the odd characteristic of producing only one offspring at a time.  Also unlike other insects, their offspring is not deposited as an egg, but is instead retained inside the female’s uterus during development, and nurtured by a milk gland.  Three other fly families share this characteristic: the Tsetse flies (family Glossinidae), and two families of bat flies (Streblidae and Nycteribiidae).  Together with the Hippoboscidae, all of these flies survive on a nutritious diet of blood taken from their host.

Because little is known about the life history and evolution of Hippo flies, our research is in an initial phase with three primary goals.  The first is to document the host-parasite relationship.  To this end, when BBBO volunteers collect specimens, they record information about the bird from which the fly was collected.  We then enter this information into a database that will allow us to determine which birds carry the heaviest loads of which species of Hippo flies.  Combined with known life-history information about the bird species, and climate data from season to season, this will give us clues regarding the life history of Hippo flies, and the conditions under which they thrive.  Our second goal is to examine the evolutionary relationships that exist among Hippo flies.  When samples are brought back to our lab, students extract and sequence DNA from each fly.  The sequence data is then used to determine their relatedness, and thus the evolutionary history of the flies.  Once we understand this evolutionary history, we can use it to ask how the physical features of these insects have evolved over time (our third goal). In preparation for this, students use a microscope camera to document many of the notable features of the flies, including the external structure of their eyes, wings, claws (which they use to hold on to the bird feathers), and proboscis (which they use to pierce the bird skin and drink their blood).  My primary interest in this regard is in the evolution of their eyes.  Eventually we hope to begin studying the interior structure of their eyes through histological analysis.  All of this information, analyzed in light of their evolutionary relationships, will help us to better understand the evolutionary forces that affect how physical features change as species evolve. (Fall 2012 – Spring 2014)

Inland and lakeshore stopover ecology of the White-throated Sparrow (Zonotrichia albicollis) in western New York

Researcher:  Christina Hoh, Masters Candidate at SUNY Brockport under the guidance of Dr. Christopher Norment of SUNY Brockport and Dr. Susan Smith Pagano of Rochester Institute of Technology

BBBO is located in an especially important stopover area; this is the last stop that many spring migrants can make to rest and refuel before making a nonstop flight across the lake.  One of the research projects taking place at BBBO this spring is an observational experiment about the stopover ecology and physiology of white-throated sparrows.  The project involves comparing migrating sparrows that stopover at BBBO and those that are netted at a farm further inland, along NY Route 31.  During the spring migration seasons of 2013 and 2014, we are exploring whether birds with different life history traits (age, sex, color morph) and physiological characteristics (size, weight, fat score) choose different stopover sites or spend their time there differently.   This research will help us learn more about how birds make decisions about stopover sites, which can be an important part of habitat conservation and restoration. (Spring 2013)

Testosterone production in songbirds on stopover during spring migration

Researcher:  K.M. Covino, Ph.D Candidate at University of Southern Mississippi

Migratory songbirds are constrained not only by a short breeding season but also by an intense journey prior to breeding, preparation for which begins prior to arrival on the breeding grounds. The goal of this project is to study breeding preparation of migrating songbirds relative to distance remaining on spring passage and to overall condition. I will determine whether birds begin breeding preparation, as measured using breeding hormones, and if so, whether preparedness is adjusted with movement closer to breeding destinations. I will sample several species of songbirds at locations that represent different distances remaining on migration.  The focus of my collaboration with Braddock Bay Bird Observatory is to compare testosterone levels of Yellow-rumped (Myrtle) Warblers (Setophaga coronata coronata) at a southern site in coastal Louisiana to those at Braddock Bay. This study design will allow me to compare how these migrants transition their physiology during the different phases of the annual cycle. (Spring 2012 and 2013)

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