18. Australia’s Urban Cavity Nesters and Introduced Parrots: Patterns, Processes, and Impacts

2021 ◽  
pp. 277-292
Author(s):  
Andrew M. Rogers ◽  
Salit Kark
Keyword(s):  
2017 ◽  
Vol 13 (1) ◽  
pp. 20160783 ◽  
Author(s):  
Gabrielle L. Davidson ◽  
Alex Thornton ◽  
Nicola S. Clayton

Strong selection pressures are known to act on animal coloration. Although many animals vary in eye colour, virtually no research has investigated the functional significance of these colour traits. Passeriformes have a range of iris colours, making them an ideal system to investigate how and why iris colour has evolved. Using phylogenetic comparative methods, we tested the hypothesis that conspicuous iris colour in passerine birds evolved in response to (a) coordination of offspring care and (b) cavity nesting, two traits thought to be involved in intra-specific gaze sensitivity. We found that iris colour and cooperative offspring care by two or more individuals evolved independently, suggesting that bright eyes are not important for coordinating parental care through eye gaze. Furthermore, we found that evolution between iris colour and nesting behaviour did occur in a dependent manner, but contrary to predictions, transitions to coloured eyes were not more frequent in cavity nesters than non-cavity nesters. Instead, our results indicate that selection away from having bright eyes was much stronger in non-cavity nesters than cavity nesters, perhaps because conspicuous eye coloration in species not concealed within a cavity would be more visible to predators.


2004 ◽  
Vol 34 (10) ◽  
pp. 2099-2109 ◽  
Author(s):  
Kathryn EH Aitken ◽  
Kathy Martin

Cavity-nesting vertebrates, a significant component of forest wildlife communities, are connected ecologically in nest webs arranged in guilds of cavity producers (strong and weak excavators) and cavity consumers. The availability of tree cavities for nesting and roosting is considered critical to maintaining communities of cavity nesters. Using univariate tests and resource selection indices, we examined nesting use of both natural and excavated cavities in small aspen–conifer groves of interior British Columbia in relation to availability of cavity, tree, and habitat features. In a 2-year study, we monitored 197 cavities for use, 8% of which were lost between years. Of those that survived, 26% were occupied in both years, 29% were used in only one year, and 45% were not used in either year. Occupied cavities were larger internally than those not occupied in either year and were more likely to be in trees with only one cavity. In species-level resource selection analyses, tree swallows (Tachycineta bicolor Vieillot), European starlings (Sturnus vulgaris L.), and chickadees (Poecile spp.) used live, heart rot infected trees more than expected from their proportional abundance and used dead trees less than expected, while northern flickers (Colaptes auratus L.), mountain bluebirds (Sialia currucoides Bechstein), and red squirrels (Tamiasciurus hudsonicus Erxleben) used live and dead trees in proportion to their availability. Managed, open landscapes with small mixed or deciduous forest groves can sustain healthy communities of cavity nesters, if there is a range of suitable trees for excavators and open areas for foraging.


1983 ◽  
Vol 7 (4) ◽  
pp. 224-229 ◽  
Author(s):  
Richard F. Harlow ◽  
David C. Guynn

Abstract The availability of pine and hardwood snags was determined in managed pine and nonpine stands on the Francis Marion National Forest in the Coastal Plain of South Carolina. An estimate was made of snags required for nesting by avian cavity nesters indigenous to the region and of the density of cavity nesters currently provided for on the forest. Avian species that use snags 5 to 9 in. d.b.h. were apparently provided with more than 100 percent of the minimum number of suitable-size snags for average bird populations in the nonpine stands, which encompassed about 30 percent of the area. In pine stands, by contrast, there were enough snags of this size for only 20 percent of the average avian populations. For species using larger snags (≥10 in. d.b.h.), nonpine stands provided enough for approximately 27 percent of average bird populations, while pine stands provided snags for only about 6 percent of average population densities.


The Condor ◽  
2004 ◽  
Vol 106 (1) ◽  
pp. 5-19 ◽  
Author(s):  
Kathy Martin ◽  
Kathryn E. H. Aitken ◽  
Karen L. Wiebe

Abstract The mixed forests of interior British Columbia, Canada, support a rich community of cavity nesters, accounting for about one-third of forest vertebrate species. For 20 cavity-nesting bird and six cavity-nesting mammal species, representing excavators and secondary cavity nesters, we measured nest-cavity and nest-tree characteristics over 8 years in Interior Douglas-fir (Pseudotsuga menziesii) forest ecosystems. There was overwhelming selection for quaking aspen (Populus tremuloides); 95% of 1692 cavity nests were in aspen, which comprised only 15% of trees available. The full range of live and dead trees were used, but we observed a strong preference for live trees with decay (45% of nests) or dead trees (45% of nests). A cluster analysis based on tree and cavity characteristics divided the community into five groups, including large- and medium-sized woodpeckers and a group comprised mostly of weak excavators. A fourth group included Northern Flickers (Colaptes auratus), the most abundant excavator, and the larger secondary cavity nesters. The final group contained the most aggressive and most abundant secondary cavity nesters. European Starling (Sturnus vulgaris), the most aggressive secondary cavity nester, occupied a narrower nest niche (in less-decayed trees with smaller entrances) relative to their size. Less-competitive excavators and secondary cavity nesters occupied wider nest niches in terms of tree decay class and cavity size. We constructed a nest web for community structure that showed most cavity resource use flowed up the community through aspen trees and cavities excavated by Northern Flickers. Thus, aspen was the critical nesting tree and Northern Flickers were the keystone excavators in this community. Sitios de Nidificación y Redes de Nidos en Comunidades que Nidifican en Cavidades en el Interior de British Columbia, Canadá: Características de los Nidos y Separación de Nichos Resumen. Los bosques mixtos del interior de British Columbia, Canadá, albergan una rica comunidad de animales que nidifican en cavidades, los cuales representan aproximadamente un tercio de las especies de vertebrados de bosque. En este estudio medimos características de las cavidades y de los árboles de nidificación para 20 especies de aves y seis de mamíferos que nidifican en cavidades (incluyendo especies excavadoras y las que utilizan cavidades secundariamente) a lo largo de ocho años en ecosistemas de bosque interior de Pseudotsuga menziesii. Hubo una selección abrumadora de árboles de la especie Populus tremuloides; el 95% de 1692 cavidades de nidificación se encontraron en árboles de esta especie, la cual comprendía sólo el 15% de los árboles disponibles. Todo el espectro de árboles vivos y muertos fue utilizado, pero observamos una preferencia fuerte por árboles vivos con descomposición (45% de los nidos) o árboles muertos (45% de los nidos). Un análisis de agrupamiento basado en características de los árboles y las cavidades dividió la comunidad en cinco grupos, incluyendo carpinteros de tamaño grande y mediano, y un grupo formado principalmente por excavadores débiles. Un cuarto grupo incluyó al carpintero Colaptes auratus (el excavador más abundante) y a las especies de mayor tamaño que nidifican en cavidades secundarias. El último grupo incluyó a las especies más abundantes y agresivas que nidifican en cavidades secundarias. El estornino Sturnus vulgaris, la especie más agresiva que nidifica en cavidades secundarias, ocupó un nicho más estrecho (árboles menos descompuestos con entradas más pequeñas) con relación a su tamaño. Los excavadores menos competitivos y los usuarios de cavidades secundarias ocuparon nichos de nidificación más amplios en términos de la categoría de descomposición de los árboles y el tamaño de la cavidad. Construimos una red de nidos para estudiar la estructura de la comunidad, la cual mostró que la mayor parte del uso de las cavidades como recurso fluye en la comunidad a través de los árboles de P. tremuloides y las cavidades excavadas por C. auratus. Por lo tanto, P. tremuloides fue el árbol de nidificación crítico y C. auratus fue la especie de excavador clave en esta comunidad.


The Condor ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 232-238 ◽  
Author(s):  
Adam M. Siepielski

Abstract Nest predation is thought to play an important role in structuring certain breeding bird communities. One potential consequence of nest predation is lower recruitment in breeding birds, which may be manifested as lower breeding bird abundance. Lodgepole pine (Pinus contorta ssp. latifolia) forests east and west of the Rocky Mountains became isolated following glacial retreat 12 000 years ago and differ in whether or not red squirrels (Tamiasciurus hudsonicus), which are a key nest predator, are present. Breeding bird abundance in lodgepole pine forests was compared between four ranges with red squirrels and four ranges without red squirrels. Species grouped into canopy and understory nesting guilds were, on average, two and three times more abundant, respectively, in forest ranges without red squirrels than in ranges with red squirrels; no statistically significant differences were found for midstory, ground, or cavity nesters. These results suggest that geographic variation in the presence or absence of red squirrels is likely important in structuring breeding bird communities in lodgepole pine forests across the landscape.


The Condor ◽  
2001 ◽  
Vol 103 (2) ◽  
pp. 268-277
Author(s):  
J. Christopher Haney ◽  
David S. Lee ◽  
Mark Wilbert

Abstract We evaluated long-term (∼50-year) change in a bird community of an extensively forested region of the southern Appalachian mountains in North Carolina and Tennessee. A species accumulation curve for a 1996–1998 survey identified a core of 50 breeding species in upper elevations of the Unicoi Mountains. Since a 1944–1946 survey, dominant species have remained identical, no species have disappeared, and mean ranked abundance of both short and long-distance migrants has not changed. Permanent residents, however, had decreased in rank by the late 1990s. Three “new” disturbance-dependent species, American Crow (Corvus brachyrhynchos), Indigo Bunting (Passerina cyanea), and Song Sparrow (Melospiza melodia), expanded into interior forest along a recently constructed parkway. Largest apparent increases in ranked abundance of individual species occurred in eight Neotropical migrants that rely upon mature, forest-interior habitat, whereas largest apparent declines in ranked abundance occurred in land-use generalists, cavity nesters, and three other Neotropical migrants. Modifications to land-use were reasonable explanations for changes in most species. Little change in community structure, greater representation of many Neotropical migrants, and virtual absence of Brown-headed Cowbirds (Molothrus ater) suggest that this large, continuous forest retained and probably regained functional integrity for forest birds during the latter half of the twentieth century.


The Condor ◽  
2002 ◽  
Vol 104 (4) ◽  
pp. 890-896 ◽  
Author(s):  
Joshua J. Lawler ◽  
Thomas C. Edwards

Abstract We compared cavity-nesting bird communities in aspen (Populus tremuloides) woodland fragments classified on the basis of vegetation structure (tree density) and landscape context (surrounding vegetation). We found very few cavity nesters in fragments predominantly surrounded by forests. Fragments adjacent to meadows contained more species and a greater abundance of cavity nesters. Species richness and abundance were higher in sparsely than in densely treed meadow fragments. Because secondary cavity nesters are often limited by cavity availability, we augmented natural cavities with nest boxes. Although only five boxes contained bird nests, these were all in sparse aspen fragments predominantly surrounded by meadows. However, we found 25 northern flying squirrel (Glaucomys sabrinus) nests in boxes, none of which were in sparse meadow fragments. In addition to highlighting the importance of landscape context in avian and mammalian habitat relationships, our results suggest that predator or competitor interactions may help structure this cavity-nester community. Composición de las Comunidades de Aves que Nidifican en Cavidades en los Fragmentos de Bosque Montano de Álamo: El Papel del Contexto del Paisaje y la Estructura del Bosque Resumen. Comparamos comunidades de aves que nidifican en cavidades en fragmentos de bosque de álamo (Populus tremuloides) clasificados en base a la estructura de la vegetación (densidad de árboles) y al contexto del paisaje (vegetación circundante). Encontramos muy pocas aves que nidifican en cavidades en los fragmentos rodeados predominantemente por bosque. Los fragmentos adyacentes a prados presentaron más especies y mayor abundancia de aves. La riqueza y la abundancia de especies fueron mayores en fragmentos con baja densidad de árboles que estuvieron rodeados por prados. Debido a que las aves que nidifican en cavidades secundarias están a menudo limitadas por la disponibilidad de cavidades, aumentamos las cavidades naturales con cajas de anidaje. Aunque solamente cinco cajas contuvieron nidos de aves, éstas estuvieron todas en los fragmentos con baja densidad de álamos rodeados predominantemente por prados. Sin embargo, encontramos 25 nidos de ardillas voladoras norteñas (Glaucomys sabrinus) en las cajas de anidaje, de las cuales ninguna estuvo en fragmentos con baja densidad de árboles rodeados por prado. Nuestros resultados destacan la importancia del contexto del paisaje en las relaciones entre el hábitat y las aves y mamíferos, y sugieren que las interacciones con depredadores o competidores pueden influenciar la estructura de la comunidades de aves que anidan en cavidades.


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