Brad Semel - Academia.edu (original) (raw)

Papers by Brad Semel

The Journal of Wildlife Management

A substantial number of bird species nest or roost in cavities (9-18% of all species in Europe, N... more A substantial number of bird species nest or roost in cavities (9-18% of all species in Europe, North America, southern Africa, and Australia). More than half of these are obligate cavity-nesters (Newton ,1994a, b). A central conservation problem facing many species is loss of breeding habitat . Considerable evidence , both observational and experimental, indicates that populations of hole-nesting birds frequently are limited by shortages of suitable nesting cavities (von Haartmann,1957; Brawn and Balda,1988; Newton, 1994a, b). Development , and the removal of large , mature timber and snags (dead trees) for commercial purposes, exacerbate these shortages. The problem is most acute for secondary cavity-nesting birds, which rely on primary cavity excavators (mainly woodpeckers), physical damage (from storms), or natural tree rot to produce cavities of sufficient size and quality.

The Journal of Wildlife Management, 1992

... Page 5. J. Wildl. Manage. 56(3):1992 BROOD PARASITISM IN WOOD DUCKS * Semel andSherman 499 di... more ... Page 5. J. Wildl. Manage. 56(3):1992 BROOD PARASITISM IN WOOD DUCKS * Semel andSherman 499 dilemma. Pages 163-170 in LH Fredrickson, GV Burger, SP Havera, DA Graber, RE Kirby, and TS Taylor, eds. Proc. 1988 North American Wood Duck Symposium, St. ...

Ecotoxicology, 2010

Poly-chlorinated biphenyls (PCBs) have been recognized as a significant contaminant in the Great ... more Poly-chlorinated biphenyls (PCBs) have been recognized as a significant contaminant in the Great Lakes ecosystem. Although PCBs are implicated in the reduced survival and reproductive success of several piscivorous bird species, the biological pathway in which PCBs bioaccumulate remains largely unknown. This study investigates the two most likely biological pathways, suggested via research on Great Lakes sport fish, by which PCBs would be acquired by common terns (Sterna hirundo), a piscivorous species of conservation concern. The first proposed pathway is through atmospheric deposition of PCBs which are subsequently acquired by filter-feeding fish (e.g., alewives, Alosa pseudoharengus). An alternative pathway is via the biodeposits of zebra mussels which are consumed by shallow water fish (e.g., round gobies, Neogobius melanostromus). Because common terns breed in near-shore sites where concentrations of zebra mussels are found, as well as forage in more pelagic environments it is possible that either or both pathways may be contributing to their PCB exposure. Field experiments and stable isotope analyses suggest the most likely pathway by which terns are exposed to PCBs is via alewives, similar to how apex predators such as lake trout acquire PCBs. Biodeposits from zebra mussels do not appear to be a significant factor in PCB accumulation in terns. We quantified extremely poor parental attentiveness during incubation. Although we cannot determine whether poor parental attentiveness alone or in combination with PCB contamination led to low hatching success, accumulation of PCBs appears to have significant impacts on the overall reproductive success of common terns.

Ecological Applications, 1992

The Condor, 1988

... in the upper story of the forest, making them difficult for humans and probably Wood Ducks to... more ... in the upper story of the forest, making them difficult for humans and probably Wood Ducks to locate initially (Prince 1965, Weier ... and the active role of nesting females in avoiding parasitism (including sur-reptitious behavior near the nest: Semel and Sherman 1986), reduce the ...

Biodiversity and Conservation, 2010

Many wetland-dependent birds are thought to be experiencing significant population declines, alth... more Many wetland-dependent birds are thought to be experiencing significant population declines, although population trend data for this suite of birds are rare and the causes of declines poorly understood. We used a 26-year dataset (1980–2005) of wetland bird abundance and distribution among 196 wetlands in northeastern Illinois (i.e., Chicago and its suburbs) to evaluate population trends and identify underlying ecological

Animal Behaviour, 2001

We investigated the behavioural mechanisms and adaptive significance of intraspecific brood paras... more We investigated the behavioural mechanisms and adaptive significance of intraspecific brood parasitism in wood ducks, Aix sponsa, by observing a colour-marked population in northeastern Illinois for seven breeding seasons (1989)(1990)(1991)(1992)(1993)(1994)(1995). The birds nested in boxes that were dispersed widely and mounted high on tree trunks, mimicking the distribution and locations of natural nesting cavities. During 158 mornings of observation, 103 parasitic eggs were laid: 44 (43%) by females that had nested in the population previously and 59 (57%) by new recruits. Parasitism was a facultative behaviour, and its occurrence varied with a female's age and contents of the box in which she had previously nested. Returning females (2-7 years old) usually laid again in last year's box, even if another female already was laying there. Each female behaved as if the box were hers. Indeed, jointly nesting females behaved so similarly that it was impossible to differentiate the 'host' from the 'parasite'. Eventually one of these females was forced to depart, often after a fight. In 66% of cases the earlier-arriving female prevailed. Displaced females left behind eggs that were 'parasitic' in the definitional sense (i.e. incubated by another female), but parasitism actually was a consequence of being evicted from a favoured nestbox. Displaced females usually laid and incubated a complete clutch in a nearby box; the following year, they again attempted to nest in the box they had used initially. New recruits to the population were younger (1-2 years old), and they often did not nest. However, they did search widely for nesting cavities. When a new recruit found a suitable site that contained an active nest, she sometimes laid a few parasitic eggs there and, in subsequent seasons, attempted to nest in the box she had parasitized. Natal females often returned to and laid in the box from which they hatched, unless it was occupied by their mother. Adult females also actively avoided parasitizing close kin. In general, a nest cavity that was previously used successfully may be worth returning to, and fighting for, because its location is known and its quality has been proven. Scarcity of preferred nesting sites is probably the key ecological factor underlying all four unusual reproductive behaviours that characterize female wood ducks and other cavity-nesting waterfowl: natal philopatry, nest-site fidelity, aggressive competition for nest sites and high levels of intraspecific parasitism.

American Midland Naturalist, 1988

ABSTRACT Both Peromyscus leucopus white-footed mice and Blarina brevicauda short-tailed shrews pr... more ABSTRACT Both Peromyscus leucopus white-footed mice and Blarina brevicauda short-tailed shrews prey upon the curculionid weevils that attack Quencus alba acorns. Peromyscus leucopus also feeds on Q. alba acorns, but B. brevicauda does not. The authors conducted feeding experiments using weevil larvae or pupae (1) to determine the relative preference of P. leucopus for infested and noninfested acorns; (2) to examine consumption rates of P. leucopus and B. brevicauda when larvae are freely available, and (3) to determine whether weevils that have exited acorns and burrowed into the soil are differentially vulnerable to these two predators. No preference by P. leucopus was detected in either field or laboratory studies where entire acorns were offered, but P. leucopus showed a significant preference for sound over infested when only nutmeat was presented.

Behavioral Ecology, 2006

We investigated the role of kinship in intraspecific nest parasitism of wood ducks (Aix sponsa). ... more We investigated the role of kinship in intraspecific nest parasitism of wood ducks (Aix sponsa). Among waterfowl, female philopatry creates the potential for female relatives to nest in proximity. Costs of intraspecific nest parasitism to host females may be reduced if parasites lay eggs with kin. However, previous observations of marked wood ducks indicated that females avoided parasitizing clutch mates or the female that incubated them. To further examine the role of kinship, we determined the genotypes of 27 host-parasite pairs at five microsatellite loci. Average relatedness between hosts and all females laying parasitic eggs was only 0.04 6 0.03. Parasites appeared to choose hosts randomly with respect to kinship from among females with nests in the neighborhood and those within the entire study area. However, host relatedness to the parasite with the greatest number of young leaving the nest was 0.11 6 0.03, which was greater than expected if eggs were accepted randomly from neighboring females or from females present on the entire study area (p ¼ .03 and p ¼ .02, respectively). These patterns may reflect parasitism of randomly selected nests followed by differential acceptance by hosts, differential hatching success of related parasites (e.g., due to greater laying synchrony), or a mixture of parasitic strategies, one with a focus on related hosts and the other on unrelated hosts. Genetic data revealed that social relationships did not always reflect true relatedness and that success of primary parasites was associated with kinship to hosts. by guest on January 22, 2016 http://beheco.oxfordjournals.org/ Downloaded from Nielsen et al. • Host-parasite relatedness in wood ducks 493 by guest on January 22, 2016 http://beheco.oxfordjournals.org/ Downloaded from by guest on January 22, 2016 http://beheco.oxfordjournals.org/ Downloaded from Nielsen et al. • Host-parasite relatedness in wood ducks 495 by guest on January 22, 2016 http://beheco.oxfordjournals.org/ Downloaded from