scholarly journals Geographic and Ecological Variation in Clutch Size of Tree Swallows

The Auk ◽  
2000 ◽  
Vol 117 (1) ◽  
pp. 215-221 ◽  
Author(s):  
Peter O. Dunn ◽  
Kevin J. Thusius ◽  
Kevin Kimber ◽  
David W. Winkler
Keyword(s):  
Clutch Size ◽  
The United States ◽  
Laying Date ◽  
Breeding Density ◽  
Tree Swallows ◽  
Breeding Bird ◽  
Resource Abundance ◽  
Strong Positive Relationship ◽  
Confounding Variables

AbstractIn many birds, populations breeding at higher latitudes have larger clutch sizes. It has been hypothesized that this relationship results from the greater availability of food at higher latitudes. We examined geographic variation in clutch size of Tree Swallows (Tachycineta bicolor) in relation to latitude, longitude, laying date, breeding density, elevation, and summer actual evapotranspiration (AE). AE is a measure of terrestrial primary productivity, and we assumed that it was correlated with resource abundance. Clutch size data were compiled from nest records throughout the breeding range in the United States and Canada (n = 7,459). Summer AE estimates were made from long-term climatological records, and breeding density was estimated from Breeding Bird Surveys. All variables were averaged for each 1° block of latitude and longitude (n = 85 latilong blocks). We found a strong positive relationship between clutch size and latitude. Absolute levels of resource abundance (summer AE) were not related to clutch size but were related inversely to latitude and longitude. After controlling for the effects of confounding variables, clutch size was related positively to latitude and relative resource abundance (summer AE after controlling for breeding density). Our results are consistent with Ashmole's hypothesis that relative, rather than absolute, levels of resource abundance determine at least some of the variation in clutch size.

The costs of reproduction in tree swallows (Tachycineta bicolor)

1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Brood Size ◽  
Life History Theory ◽  
Tachycineta Bicolor ◽  
Laying Date ◽  
Tree Swallows ◽  
Costs Of Reproduction ◽  
Return Rates ◽  
Trade Offs

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.

scholarly journals Warmer springs, laying date and clutch size of tree sparrows Passer montanus in Croatia

2011 ◽  
Vol 57 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Z. Dolenec ◽  
P. Dolenec ◽  
A.P. Møller
Keyword(s):  
Clutch Size ◽  
Laying Date ◽  
Negative Effects ◽  
Spring Temperature ◽  
Temperature Changes ◽  
Passer Montanus ◽  
Air Temperatures ◽  
Socially Monogamous ◽  
Extreme Change

Abstract Global surface air temperatures increased during the past 100 years. Many long-term studies of birds have reported a climatic influence on breeding performance. We analysed long-term changes in first laying date and clutch size for first clutches of sedentary, hole-nesting and socially monogamous tree sparrows Passer montanus during 1980–2009 in northwestern Croatia. Laying date advanced and spring temperature increased significantly during the study. Date of laying was significantly correlated with mean air spring temperature and advanced by 8.6 days during the 30 years period. Laying date was delayed in extremely cold, but not in extremely warm springs compared to years with normal temperatures. These results suggest that current climate change including extreme change does not have negative effects on timing of laying or clutch size. In contrast to laying date, clutch size did not vary systematically during the study period or with mean spring air temperature changes.

Attributes of long-term heavy cannabis users: a case–control study

2003 ◽  
Vol 33 (8) ◽  
pp. 1415-1422 ◽  
Author(s):  
A. J. GRUBER ◽  
H. G. POPE ◽  
J. I. HUDSON ◽  
D. YURGELUN-TODD
Keyword(s):  
Social Life ◽  
Subjective Effects ◽  
The United States ◽  
Case Control ◽  
Self Report ◽  
Negative Effects ◽  
Heavy Users ◽  
Confounding Variables ◽  
Negative Effect

Background. Although cannabis is the most widely used illicit drug in the United States, few recent American studies have examined the attributes of long-term heavy cannabis users.Method. Using a case–control design, we obtained psychological and demographic measures on 108 individuals, age 30–55, who had smoked cannabis a mean of 18000 times and a minimum of 5000 times in their lives. We compared these heavy users to 72 age-matched control subjects who had smoked at least once, but no more than 50 times in their lives.Results. We found no significant differences between the two groups on reported levels of income and education in their families of origin. However, the heavy users themselves reported significantly lower educational attainment (P<0·001) and income (P=0·003) than the controls, even after adjustment for a large number of potentially confounding variables. When asked to rate the subjective effects of cannabis on their cognition, memory, career, social life, physical health and mental health, large majorities of heavy users (66–90%) reported a ‘negative effect’. On several measures of quality of life, heavy users also reported significantly lower levels of satisfaction than controls.Conclusion. Both objective and self-report measures suggest numerous negative features associated with long-term heavy cannabis use. Thus, it seems important to understand why heavy users continue to smoke regularly for years, despite acknowledging these negative effects. Such an understanding may guide the development of strategies to treat cannabis dependence.

Implantation of the eSVS Mesh: Modification of Recommended Technique

2015 ◽  
Vol 10 (2) ◽  
pp. 146-149 ◽  
Author(s):  
Robert W. Emery ◽  
Eric Solien ◽  
John D. Puskas
Keyword(s):  
Vein Graft ◽  
Saphenous Vein Graft ◽  
Neointimal Hyperplasia ◽  
Graft Patency ◽  
The United States ◽  
Feasibility Trial ◽  
Confounding Variables ◽  
Vein Bypass ◽  
Implant Technique

The eSVS Mesh is a knitted wire lattice manufactured in cylindrical sheaths of various diameters, designed to be placed around the outer surface of a saphenous vein graft before use in coronary surgery. The goal is to improve long-term vein graft patency by preventing expansive endothelial injury obviating neointimal hyperplasia and subsequent graft atherosclerosis. Since the First-In-Man feasibility trial of the eSVS Mesh, postmarket studies in Europe and a feasibility trial in the United States are ongoing. Consensus from the principal investigators indicated the trials had confounding variables that may impact results other than evaluation of the eSVS Mesh alone. With input from these investigators, the recommended operative technique has been modified for future trials by removing the mesh from proximal and distal anastomoses and eliminating the use of fibrin sealant. These changes allow for use of an implant technique closer to standard vein bypass grafting and a more focused evaluation of the eSVS Mesh.

Long-Term Variation in Laying Date and Clutch Size of the Great TitParus majorin Central Poland: A Comparison between Urban Parkland and Deciduous Forest

Ardeola ◽  
2015 ◽  
Vol 62 (2) ◽  
pp. 311-322 ◽  
Author(s):  
Jarosław Wawrzyniak ◽  
Adam Kaliński ◽  
Michał Glądalski ◽  
Mirosława Bańbura ◽  
Marcin Markowski ◽  
...  
Keyword(s):  
Clutch Size ◽  
Deciduous Forest ◽  
Laying Date ◽  
Central Poland ◽  
Term Variation

Speech-Language Pathology in the Peace Corps: Necessity and Sustainability

2012 ◽  
Vol 2 (1) ◽  
pp. 11-18
Author(s):  
Melissa A. Pierce
Keyword(s):  
United States ◽  
Special Education ◽  
Peace Corps ◽  
People With Disabilities ◽  
Communication Disorders ◽  
The United States ◽  
Speech Language Pathology ◽  
Speech Language Pathologists ◽  
Language Pathology

In countries other than the United States, the study and practice of speech-language pathology is little known or nonexistent. Recognition of professionals in the field is minimal. Speech-language pathologists in countries where speech-language pathology is a widely recognized and respected profession often seek to share their expertise in places where little support is available for individuals with communication disorders. The Peace Corps offers a unique, long-term volunteer opportunity to people with a variety of backgrounds, including speech-language pathologists. Though Peace Corps programs do not specifically focus on speech-language pathology, many are easily adapted to the profession because they support populations of people with disabilities. This article describes how the needs of local children with communication disorders are readily addressed by a Special Education Peace Corps volunteer.

Multidisciplinary Evidence to Treat Bilingual Individuals with Aphasia

2008 ◽  
Vol 15 (3) ◽  
pp. 66-72 ◽  
Author(s):  
José G. Centeno
Keyword(s):  
Stroke Rehabilitation ◽  
Culturally Diverse ◽  
Treatment Strategies ◽  
The United States ◽  
Intervention Strategies ◽  
Steady Increase ◽  
Clinical Procedures ◽  
Bilingual Speakers ◽  
Aphasic Clients

Abstract The steady increase in linguistic and cultural diversity in the country, including the number of bilingual speakers, has been predicted to continue. Minorities are expected to be the majority by 2042. Strokes, the third leading cause of death and the leading cause of long-term disability in the U.S., are quite prevalent in racial and ethnic minorities, so population estimates underscore the imperative need to develop valid clinical procedures to serve the predicted increase in linguistically and culturally diverse bilingual adults with aphasia in post-stroke rehabilitation. Bilingualism is a complex phenomenon that interconnects culture, cognition, and language; thus, as aphasia is a social phenomenon, treatment of bilingual aphasic persons would benefit from conceptual frameworks that exploit the culture-cognition-language interaction in ways that maximize both linguistic and communicative improvement leading to social re-adaptation. This paper discusses a multidisciplinary evidence-based approach to develop ecologically-valid treatment strategies for bilingual aphasic individuals. Content aims to spark practitioners' interest to explore conceptually broad intervention strategies beyond strictly linguistic domains that would facilitate linguistic gains, communicative interactions, and social functioning. This paper largely emphasizes Spanish-English individuals in the United States. Practitioners, however, are advised to adapt the proposed principles to the unique backgrounds of other bilingual aphasic clients.

Traumatic Brain Injury: A Trauma Surgeon's Perspective

2012 ◽  
Vol 22 (3) ◽  
pp. 82-89
Author(s):  
Oscar D. Guillamondegui
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Multidisciplinary Approach ◽  
Trauma Team ◽  
The United States ◽  
Long Term Outcomes ◽  
Term Care ◽  
Injured Brain ◽  
The Moment

Traumatic brain injury (TBI) is a serious epidemic in the United States. It affects patients of all ages, race, and socioeconomic status (SES). The current care of these patients typically manifests after sequelae have been identified after discharge from the hospital, long after the inciting event. The purpose of this article is to introduce the concept of identification and management of the TBI patient from the moment of injury through long-term care as a multidisciplinary approach. By promoting an awareness of the issues that develop around the acutely injured brain and linking them to long-term outcomes, the trauma team can initiate care early to alter the effect on the patient, family, and community. Hopefully, by describing the care afforded at a trauma center and by a multidisciplinary team, we can bring a better understanding to the armamentarium of methods utilized to treat the difficult population of TBI patients.

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