Ricklefs, Robert E. An Analysis of Nesting Mortality in Birds. Smithsonian Contributions to Zoology, 9:1-48. 1969.—This study was initiated to evaluate nesting mortality of birds as a feature of the environment and as a selective force in the evolution of reproductive strategies. Representative nesting-success data from the literature for most groups of birds were transformed into daily mortality rates to eliminate differences among species in the length of the nest cycle. These data are presented by taxonomic groupings and for passerines by geographical region and nest construction and placement. The strength and pattern of various mortality factors are described in detail. Predation, starvation, desertion, hatching failure, and adverse weather are the most prevalent factors, but nestsite competition, brood parasitism, and arthropod infestation may be important in some species. It is demonstrated that the various mortality factors can be identified by characteristic patterns of nesting losses involving differences in mortality rates between the egg and nestling periods and the within-nest component of mortality rates. Among Temperate Zone passerines, field-nesting and marsh-nesting species have the highest mortality rates while those species nesting in trees, especially in cavities, enjoy higher success. Starvation is prevalent in marsh and field species but desertion is more restricted to tree-nesting species. In general, arctic species have lower mortality rates and tropical species higher rates, although there is a similar gradient from arid to humid regions within the tropics. The relative abundance of a species is related directly to its mortality rate in arctic regions, but is not in temperate and tropical regions. Birds of prey generally have low mortality rates although starvation is often a major factor. Nesting losses in seabirds are caused primarily by crowded conditions in colonies and loss of eggs due to inadequate nest construction. Chick deaths come about primarily through their wandering away from parental care which is most common in the semiprecocial Charadriiformes. Precocial shorebirds and water birds enjoy higher egg success than ground-nesting passerines but game birds exhibit similar mortality rates. Little is known of the survival of precocial chicks after hatching except that mortality rates may be initially quite high and decrease with age. The fate of altricial birds after fledging is also poorly documented. It is postulated that interspecific differences in mortality rates are determined by evolutionarily acceptable levels of adult risk to lower mortality rates of offspring through parental care, adult adaptations of morphology and behavior for foraging which result in limitations on nesting adaptations, environmental unpredictability which reduces the effectiveness of adaptations, and—most import—the diversity of predators to which a species must adapt. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1969 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Price 55 cents (paper cover)

An analysis of nesting mortality in birds

Publisher Summary The chapter describes a simple economic model that predicts in a qualitative way on how costs (lost feeding opportunity and risk) interact to produce an optimal flight distance from approaching predators. Animals often defer the decision to flee from an approaching predator and continue with their ongoing activities. The view is that, a profitable approach to the problem of why such decisions are deferred, and how they are eventually made, is to view the process as an economic, one in which the relative costs of fleeing and staying change as a predator approaches. It is suggested that the economic approach will prove useful in analyzing many aspects of predator-prey interactions.

The Economics of Fleeing from Predators

Alkaloids mimicking the structures of monosaccharides are now believed to be widespread in plants and microorganisms, and these sugar mimics inhibit glycosidases because of a structural resemblance to the sugar moiety of the natural substrate. Naturally occurring sugar mimics with a nitrogen in the ring are classified into five structural classes: polyhydroxylated piperidines, pyrrolidines, indolizidines, pyrrolizidines and nortropanes. Glycosidases are involved in a wide range of important biological processes, such as intestinal digestion, post-translational processing of glycoproteins and the lysosomal catabolism of glycoconjugates. The realization that alkaloidal sugar mimics might have enormous therapeutic potential in many diseases such as viral infection, cancer and diabetes has led to increasing interest and demand for these compounds. Most of these effects can be shown to result from the direct or indirect inhibition of glycosidases. The glycosphingolipid (GSL) storage diseases are relatively rare hereditary disorders that are severe in nature and frequently fatal. Possible strategies for the treatment of these lysosomal storage diseases include enzyme replacement therapy, gene therapy and substrate deprivation. Recently, quite a new therapy for lysosomal storage diseases has been reported, namely a ‘chemical chaperone therapy’ for Fabry disease. In this report, the structural basis for the specificity of inhibition of alkaloidal sugar mimics and their current and potential application to biomedical problems will be reviewed.

Sugar-mimic glycosidase inhibitors: natural occurrence, biological activity and prospects for therapeutic application

Many putative examples of coevolution do not stand up to critical analysis. A rigorous definition of coevolution requires that a trait in one species has evolved in response to a trait of another species, which trait was itself evolved in response to the first species (50, 69). This type of intimate, reciprocal evolutionary relationship is hard to demonstrate because most species interact with many other species, all of which may affect their evolution. For example, a host species is likely to be affected by many types of parasitic helminths and protozoans. Accordingly, some of its defenses will be fairly general and not attributable to any particular species of parasite. Such situations are termed diffuse coevolution, as opposed to pairwise coevolution in which adaptations have a stepwise, reciprocal nature. Unfortunately, diffuse coevolution is difficult to document because additional species may need to be considered. Also, adapting to many species may compromise adaptations to any one species so much that coevolutionary traits are weakly expressed and hard to identify. Systems in which the interacting species are few (optimally only two) provide the clearest examples of coevolution. Such systems include many mutualistic relationships and some parasite-host associations (51). Among the latter, brood parasitism provides some of the most persuasive examples of coevolution because it often involves small numbers of species.

A Model System for Coevolution: Avian Brood Parasitism

A model system of coevolution: avian brood parasitism.

Host–brood parasite interactions may not always be as they seem.

The Advantage of being Parasitized

α-Homonojirimycin [2,6-dideoxy-2,6-imino-d-glycero-l-gulo-heptitol] from omphalea diandra L.: isolation and glucosidase inhibtion

α-Homonojirimycin and 2,5-dihydroxymethyl-3,4-dihydroxy-pyrrolidine: Alkaloidal glycosidase inhibitors in the moth Urania fulgens

Hybridization provides a unique perspective into the ecological, genetic and behavioral context of speciation. Hybridization is common in birds, but has not yet been reported among bird species with a simultaneously polyandrous mating system; a mating system where a single female defends a harem of males who provide nearly all parental care. Unlike simple polyandry, polyandrous mating is extremely rare in birds, with only 1% of bird species employing this mating system. Although it is classically held that females are "choosy" in avian hybrid systems, nearly-exclusive male parental care raises the possibility that female selection against heterospecific matings might be reduced compared to birds with other mating systems. We describe a narrow hybrid zone in southwestern Panama between two polyandrous freshwater waders: Northern Jacana, Jacana spinosa and Wattled Jacana, J. jacana. We document coincident cline centers for three phenotypic traits, mtDNA, and one of two autosomal introns. Cline widths for these six markers varied from seven to 142 km, with mtDNA being the narrowest, and five of the six markers having widths less than 100 km. Cline tails were asymmetrical, with greater introgression of J. jacana traits extending westward into the range of J. spinosa. Likewise, within the hybrid zone, the average hybrid index of phenotypic hybrids was significantly biased towards J. spinosa. Species distribution models indicate that the hybrid zone is located at the edge of a roughly 100 km wide overlap where habitat is predicted to be suitable for both species, with more westerly areas suitable only for spinosa and eastward habitats suitable only for J. jacana. The two species of New World jacanas maintain a narrow, and persistent hybrid zone in western Panama. The hybrid zone may be maintained by the behavioral dominance of J. spinosa counterbalanced by unsuitable habitat for J. spinosa east of the contact zone. Although the two parental species are relatively young, mitochondrial cline width was extremely narrow. This result suggests strong selection against maternally-inherited markers, which may indicate either mitonuclear incompatibilities and/or female choice against heterospecific matings typical of avian hybrid systems, despite jacana sex role reversal.

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Neal Griffith Smith

Papers

The Advantage of being Parasitized

α-Homonojirimycin [2,6-dideoxy-2,6-imino-d-glycero-l-gulo-heptitol] from omphalea diandra L.: isolation and glucosidase inhibtion

α-Homonojirimycin and 2,5-dihydroxymethyl-3,4-dihydroxy-pyrrolidine: Alkaloidal glycosidase inhibitors in the moth Urania fulgens

Genetic and phenotypic characterization of a hybrid zone between polyandrous Northern and Wattled Jacanas in Western Panama

Provoked release of mobbing‐a hunting technique of micrastur falcons