Ornithology Commons^™

Eggshell Pigment Composition Covaries With Phylogeny, Kaat Brulez, Ivan Miksik, Christopher R. Cooney, Mark E. Hauber, Paul George Lovell, Golo Maurer, Steven J. Portugal, Douglas Russell, Silas James Reynolds, Phillip Cassey

Publications and Research

No single hypothesis is likely to explain the diversity in eggshell coloration and patterning across birds, suggesting that eggshell appearance is most likely to have evolved to fulfill many nonexclusive functions. By controlling for nonindependent phylogenetic associations between related species, we describe this diversity using museum eggshells of 71 British breeding passerine species to examine how eggshell pigment composition and concentrations vary with phylogeny and with life-history and nesting ecology traits. Across species, concentrations of biliverdin and protoporphyrin, the two main pigments found in eggshells, were strongly and positively correlated, and both pigments strongly covaried with phylogenetic relatedness. Controlling for …

Core And Shell Song Systems Unique To The Parrot Brain, Mukta Chakraborty, Solveig Walloe, Signe Nedergaard, Emma E. Fridel, Torben Dabelsteen, Bente Pakkenberg, Mads F. Bertelsen, Gerry M. Dorrestein, Steven E. Brauth, Sarah E. Durand, Erich D. Jarvis

Publications and Research

The ability to imitate complex sounds is rare, and among birds has been found only in parrots, songbirds, and hummingbirds. Parrots exhibit the most advanced vocal mimicry among non-human animals. A few studies have noted differences in connectivity, brain position and shape in the vocal learning systems of parrots relative to songbirds and hummingbirds. However, only one parrot species, the budgerigar, has been examined and no differences in the presence of song system structures were found with other avian vocal learners. Motivated by questions of whether there are important differences in the vocal systems of parrots relative to other vocal …

Using 3d Printed Eggs To Examine The Egg-Rejection Behaviour Of Wild Birds, Branislav Igic, Valerie Nunez, Henning U. Voss, Rebecca Croston, Zachary Aidala, Analía V. López, Aimee Van Tatenhove, Mandë E. Holford, Matthew D. Shawkey, Mark E. Hauber

Publications and Research

The coevolutionary relationships between brood parasites and their hosts are often studied by examining the egg rejection behaviour of host species using artificial eggs. However, the traditional methods for producing artificial eggs out of plasticine, plastic, wood, or plaster-of-Paris are laborious, imprecise, and prone to human error. As an alternative, 3D printing may reduce human error, enable more precise manipulation of egg size and shape, and provide a more accurate and replicable protocol for generating artificial stimuli than traditional methods. However, the usefulness of 3D printing technology for egg rejection research remains to be tested. Here, we applied 3D printing …

Climate And Changing Winter Distribution Of Alcids In The Northwest Atlantic, Richard R. Veit, Lisa L. Manne

Publications and Research

Population level impacts upon seabirds from changing climate are increasingly evident, and include effects on phenology, migration, dispersal, annual survivorship, and reproduction. Most population data on seabirds derive from nesting colonies; documented climate impacts on winter ecology are scarce. We studied interannual variability in winter abundance of six species of alcids (Charadriiformes, Alcidae) from a 58-year time series of data collected in Massachusetts 1954–2011. We used counts of birds taken during fall and winter from coastal vantage points. Counts were made by amateur birders, but coverage was consistent in timing and location. We found significant association between winter abundance of …

Experimental Shifts In Intraclutch Egg Color Variation Do Not Affect Egg Rejection In A Host Of A Non-Egg-Mimetic Avian Brood Parasite, Rebecca Croston, Mark E. Hauber

Publications and Research

Avian brood parasites lay their eggs in the nests of other birds, and impose the costs associated with rearing parasitic young onto these hosts. Many hosts of brood parasites defend against parasitism by removing foreign eggs from the nest. In systems where parasitic eggs mimic host eggs in coloration and patterning, extensive intraclutch variation in egg appearances may impair the host’s ability to recognize and reject parasitic eggs, but experimental investigation of this effect has produced conflicting results. The cognitive mechanism by which hosts recognize parasitic eggs may vary across brood parasite hosts, and this may explain variation in experimental …

Now You See It, Now You Don’T: Flushing Hosts Prior To Experimentation Can Predict Their Responses To Brood Parasitism, Daniel Hanley, Peter Samas, Josef Heryán, Mark E. Hauber, Tomáš Grim

Publications and Research

Brood parasitic birds lay their eggs in other birds’ nests, leaving hosts to raise their offspring. To understand parasite-host coevolutionary arms races, many studies have examined host responses to experimentally introduced eggs. However, attending parents often need to be flushed from their nests to add experimental eggs. If these birds witness parasitism events, they may recognize and reject foreign eggs more readily than parents who did not. We found that, after being flushed, female blackbirds, Turdus merula, remained close to their nests. Flushed females were more likely to eject foreign eggs and did so more quickly than females that …

Nesting Behaviour Influences Species-Specific Gas Exchange Across Avian Eggshells, Steven J. Portugal, Golo Maurer, Gavin H. Thomas, Mark E. Hauber, Tomáš Grim, Phillip Cassey

Publications and Research

Carefully controlled gas exchange across the eggshell is essential for the development of the avian embryo. Water vapour conductance (GH2O) across the shell, typically measured as mass loss during incubation, has been demonstrated to optimally ensure the healthy development of the embryo while avoiding desiccation. Accordingly, eggs exposed to sub-optimal gas exchange have reduced hatching success. We tested the association between eggshell GH2O and putative life-history correlates of adult birds, ecological nest parameters and physical characteristics of the egg itself to investigate how variation in GH2O has evolved to maintain optimal water loss across a diverse set of nest environments. …

Naïve Hosts Of Avian Brood Parasites Accept Foreign Eggs, Whereas Older Hosts Fine-Tune Foreign Egg Discrimination During Laying, Csaba Moskát, Miklós Bán, Mark E. Hauber

Publications and Research

Background: Many potential hosts of social parasites recognize and reject foreign intruders, and reduce or altogether escape the negative impacts of parasitism. The ontogenetic basis of whether and how avian hosts recognize their own and the brood parasitic eggs remains unclear. By repeatedly parasitizing the same hosts with a consistent parasitic egg type, and contrasting the responses of naïve and older breeders, we studied ontogenetic plasticity in the rejection of foreign eggs by the great reed warbler (Acrocephalus arundinaceus), a host species of the common cuckoo (Cuculus canorus).

Results: In response to experimental parasitism before the …

Host Responses To Interspecific Brood Parasitism: A By-Product Of Adaptations To Conspecific Parasitism?, Peter Samas, Mark E. Hauber, Phillip Cassey, Tomáš Grim

Publications and Research

Background: Why have birds evolved the ability to reject eggs? Typically, foreign egg discrimination is interpreted as evidence that interspecific brood parasitism (IP) has selected for the host’s ability to recognize and eliminate foreign eggs. Fewer studies explore the alternative hypothesis that rejection of interspecific eggs is a by-product of host defenses, evolved against conspecific parasitism (CP). We performed a large scale study with replication across taxa (two congeneric Turdus thrushes), space (populations), time (breeding seasons), and treatments (three types of experimental eggs), using a consistent design of egg rejection experiments (n = 1057 nests; including controls), in areas with …

Nest Destruction Elicits Indiscriminate Con- Versus Heterospecific Brood Parasitism In A Captive Bird, Rachel C. Shaw, William E. Feeney, Mark E. Hauber

Publications and Research

Following nest destruction, the laying of physiologically committed eggs (eggs that are ovulated, yolked, and making their way through the oviduct) in the nests of other birds is considered a viable pathway for the evolution of obligate interspecific brood parasitism. While intraspecific brood parasitism in response to nest predation has been experimentally demonstrated, this pathway has yet to be evaluated in an interspecific context. We studied patterns of egg laying following experimental nest destruction in captive zebra finches, Taeniopygia guttata, a frequent intraspecific brood parasite. We found that zebra finches laid physiologically committed eggs indiscriminately between nests containing conspecific eggs …

Project Safe Flight: Making New York Safe For Migratory Birds, Kaitlyn L. Parkins, Susan B. Elbin Ph.D., Adriana Palmer, Darren Klein, Elle Barnes

Publications and Research

More than 100 species of migratory birds pass through New York City during spring and fall migrations. Located at the nexus of several migratory routes, New York City’s tall buildings and reflective glass pose a serious threat to over 100 species of migratory birds. Since 1997, NYC Audubon has led Project Safe Flight (PSF), a volunteer-based citizen-science project, with the goal of monitoring and mitigating bird collisions. We examined 16 years of PSF data, during which volunteers collected over 6,000 birds of 126 different species. The top two species, White-throated Sparrow and Common Yellowthroat, make up 23% of all collisions. …

Assessing Regional And Interspecific Variation In Threshold Responses Of Forest Breeding Birds Through Broad Scale Analyses, Yntze Van Der Hoek, Rosalind Renfrew, Lisa L. Manne

Publications and Research

Background: Identifying persistence and extinction thresholds in species-habitat relationships is a major focal point of ecological research and conservation. However, one major concern regarding the incorporation of threshold analyses in conservation is the lack of knowledge on the generality and transferability of results across species and regions. We present a multi-region, multi-species approach of modeling threshold responses, which we use to investigate whether threshold effects are similar across species and regions.

Methodology/Principal Findings: We modeled local persistence and extinction dynamics of 25 forest-associated breeding birds based on detection/non-detection data, which were derived from repeated breeding bird atlases for the state …

Morph Matters: Aggression Bias In A Polymorphic Sparrow, Brent M. Horton, Mark E. Hauber, Donna L. Maney

Publications and Research

In species with discrete morphs exhibiting alternative behavioral strategies, individuals may vary their aggressive behavior in competitive encounters according to the phenotype of their opponent. Such aggression bias has been documented in multiple polymorphic species evolving under negative frequency-dependent selection, but it has not been well-studied under other selection regimes. We investigated this phenomenon in white-throated sparrows (Zonotrichia albicollis), a passerine with plumage polychromatism maintained by disassortative mating. The two distinct color morphs differ with respect to reproductive strategy in that white-striped birds invest more in territorial aggression than tan-striped birds. Whether territorial aggression in this species is biased according …