An additional field method to sex adult Barn Swallows during the non-breeding season in Zambia: white spot length in the outer tail feather

Shed-like structures are being built to provide Barn Swallow (Hirundo rustica erythrogaster) nesting habitat in response to population declines. However, Barn Swallow use of these structures is unavailable in the literature. We conducted three manipulative experiments to test if adding conspecific cues (i.e., vocalizations and decoys) to newly-built structures affected prospecting visits by Barn Swallows (1) during pre-breeding, (2) during post-breeding, and (3) during or after broadcasts of vocalizations compared to before broadcasts. Additionally, we monitored nesting following pre- and post-breeding cues. We built one nesting structure with and one without conspecific cues at each of 10 study sites in southern Ontario, Canada where nesting habitat was recently lost. We detected about twice as many Barn Swallows immediately after conspecific broadcasts compared to before. We did not find substantial differences in abundance and interactions with new nesting structures for other comparisons involving conspecific cues. Following pre-breeding cues at 10 sites, six nests were built in three of 10 structures treated with conspecific cues, compared to five nests in four of 10 structures without cues. In the subsequent breeding season following post-breeding cues at eight sites, four nests were built in two of eight structures treated with conspecific cues, compared to four nests in three of eight structures without cues. Conspecific vocalizations appeared to increase prospecting behaviour, but not the number of nests, at new nesting structures. The paucity of nests on new structures suggests that building shed-like structures may not be an effective method of mitigating loss of nesting habitat.

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Novel methods reveal shifts in migration phenology of barn swallows in South Africa

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2011.1897 ◽

2011 ◽

Vol 279 (1733) ◽

pp. 1485-1490 ◽

Cited By ~ 27

Author(s):

Res Altwegg ◽

Kristin Broms ◽

Birgit Erni ◽

Phoebe Barnard ◽

Guy F. Midgley ◽

...

Keyword(s):

South Africa ◽

Breeding Season ◽

Environmental Variability ◽

Southern Oscillation ◽

Bird Species ◽

Breeding Population ◽

Migratory Bird ◽

Recent Climate ◽

Breeding Grounds ◽

Barn Swallows

Many migratory bird species, including the barn swallow ( Hirundo rustica ), have advanced their arrival date at Northern Hemisphere breeding grounds, showing a clear biotic response to recent climate change. Earlier arrival helps maintain their synchrony with earlier springs, but little is known about the associated changes in phenology at their non-breeding grounds. Here, we examine the phenology of barn swallows in South Africa, where a large proportion of the northern European breeding population spends its non-breeding season. Using novel analytical methods based on bird atlas data, we show that swallows first arrive in the northern parts of the country and gradually appear further south. On their north-bound journey, they leave South Africa rapidly, resulting in mean stopover durations of 140 days in the south and 180 days in the north. We found that swallows are now leaving northern parts of South Africa 8 days earlier than they did 20 years ago, and so shortened their stay in areas where they previously stayed the longest. By contrast, they did not shorten their stopover in other parts of South Africa, leading to a more synchronized departure across the country. Departure was related to environmental variability, measured through the Southern Oscillation Index. Our results suggest that these birds gain their extended breeding season in Europe partly by leaving South Africa earlier, and thus add to scarce evidence for phenology shifts in the Southern Hemisphere.

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Relationship between sexual signals and louse (Insecta: Phthiraptera) infestation of breeding and migrating Barn swallows (Hirundo rustica) in Hungary

Ornis Hungarica ◽

10.2478/orhu-2013-0003 ◽

2012 ◽

Vol 20 (1) ◽

pp. 37-43 ◽

Cited By ~ 1

Author(s):

Enikő Gál ◽

Tibor Csörgő ◽

Zoltán Vas

Keyword(s):

Breeding Season ◽

Tail Length ◽

Significant Negative Correlation ◽

Breeding Birds ◽

Hirundo Rustica ◽

Louse Infestation ◽

Physical Interactions ◽

Barn Swallows ◽

The Difference ◽

The Relationship

Abstract Lice (Phthiraptera) chew characteristic holes on the remiges and rectrices of Barn swallows (Hirundo rustica). The number of these holes correlate positively with the intensity of louse infestation, hence hole counts are useful to quantify lousiness. Several papers showed that lice affect both life expectancy and reproductive success of hosts. In male Barn swallows, the length of the outermost tail feathers act as a sexual signal. Females prefer long-tailed males, which have significantly fewer feather holes. In this study we sampled breeding and migrating Barn swallows and compared their louse burden, and the relationship between tail length and the number of feather holes. We found significant negative correlation between feather holes and tail length in breeding males; however, we found non-significant correlation in migrating males. We suggest that attractive males have more physical interactions (e.g. extra-pair copulation) during the breeding season, than less attractive males, hence they are more exposed to louse transmission, and therefore the difference in the infestation declines towards the end of the breeding season. However, given that migrating swallow groups include colonial and solitary breeding birds, it cannot be excluded that a potentially different louse distribution on solitary breeding birds may contribute to the results.

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Lower breeding success in a new range: No evidence for the enemy release hypothesis in South American Barn Swallows

The Auk ◽

10.1093/auk/ukz050 ◽

2019 ◽

Vol 136 (4) ◽

Author(s):

Facundo A Gandoy ◽

Kaspar Delhey ◽

David W Winkler ◽

Giselle Mangini ◽

Juan I Areta

Keyword(s):

North America ◽

South America ◽

Clutch Size ◽

Breeding Season ◽

Breeding Success ◽

Enemy Release Hypothesis ◽

Enemy Release ◽

South American ◽

The South ◽

Barn Swallows

Abstract It is widely assumed that colonizing species thrive because they lack natural enemies in their new range, increasing their survival and reproductive success. Barn Swallows (Hirundo rustica) started to breed in South America around 1980 and since then have dramatically increased their population size and geographic range, in stark contrast to the decline of the source population in North America. The reasons behind the growth of the South American population are unknown. However, because this species had never bred in this area in recorded times, the lack of natural predators, parasites, or pathogens could lead to higher breeding success, as predicted by the enemy release hypothesis. Here, we test whether breeding success is higher in the newly colonized range than in the native range to test the enemy release hypothesis. We studied the breeding biology of South American Barn Swallows quantifying 7 breeding parameters: clutch size, overall breeding success, offspring mortality by predation and ectoparasites, number of fledglings per breeding attempt, number of breeding attempts per breeding season, and total number of fledglings produced per pair per breeding season. Additionally, we compared these parameters with published information from North American populations using meta-analyses. We found that, while clutch size did not differ between North and South American populations, the southern population overall had lower breeding success, with higher mortality from predation and ectoparasites. An egg laid in South America was 2.6 times more likely to fail than one laid in North America, which resulted on average in 1.1 fewer fledglings per pair per breeding season for the South American breeding population. These results, demonstrating lower breeding success in a newly colonized range, do not support the enemy release hypothesis, and indicate that the growth of the South American Barn Swallow population is most likely caused by other demographic factors.

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Gregarious foraging in barn swallows after the breeding season

Journal of Ethology ◽

10.1007/s10164-004-0143-1 ◽

2005 ◽

Vol 23 (2) ◽

pp. 139-146 ◽

Cited By ~ 2

Author(s):

Go Fujita ◽

Hiroyoshi Higuchi

Keyword(s):

Breeding Season ◽

Barn Swallows

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Host–symbiont relationship and abundance of feather mites in relation to age and body condition of the barn swallow (Hirundo rustica): an experimental study

Canadian Journal of Zoology ◽

10.1139/z05-100 ◽

2005 ◽

Vol 83 (8) ◽

pp. 1059-1066 ◽

Cited By ~ 16

Author(s):

Péter László Pap ◽

Jácint Tökölyi ◽

Tibor Szép

Keyword(s):

Reproductive Potential ◽

Breeding Population ◽

Hirundo Rustica ◽

Laying Date ◽

Tail Feather ◽

Feather Mites ◽

Second Year Of Life ◽

Barn Swallows ◽

Second Year ◽

The Difference

We analyzed the host–symbiont relationship and factors determining the abundance of feather mites among individual barn swallows (Hirundo rustica L., 1758) in two different host populations during the breeding season and postbreeding period. By experimentally removing the feather mites from the flight feathers of the birds with an insecticide, we showed that these symbiotic organisms have neither harmful nor beneficial effects on the fitness of the host, supporting the view that mites are commensals. This was indicated by the lack of any difference in the change in wing-feather length, tail-feather length, fluctuating asymmetry in tail-feather length, breeding performance, and survival of the birds between the fumigated and control groups 1 year after the experiment. During the postbreeding period juveniles harbored fewer mites than adults and the difference was also significant between the 1-year-old birds and those over 1 year old in the breeding population. The number of mites did not change after the second year of life of the birds. We hypothesize that the difference in abundance of mites between the age classes can be explained by the low reproductive potential of the mites, which are not able to populate the exploitable space until the second year of life of the host. Alternatively, young birds might provide fewer resources than old birds. The significant negative association between the number of mites and the laying date of female barn swallows seems to support the conclusion that the abundance of mites is condition-dependent. Because there was no relationship between other condition indices for males and females and number of mites, further research is needed to confirm this conclusion.

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Does prey availability affect the reproductive performance of Barn Swallows (Hirundo rustica) breeding in Ontario, Canada?

Canadian Journal of Zoology ◽

10.1139/cjz-2019-0001 ◽

2019 ◽

Vol 97 (11) ◽

pp. 979-987

Author(s):

Beverly McClenaghan ◽

Kevin C.R. Kerr ◽

Erica Nol

Keyword(s):

Breeding Season ◽

Food Availability ◽

Prey Availability ◽

Food Limitation ◽

Population Decline ◽

Reproductive Behaviour ◽

Hirundo Rustica ◽

Barn Swallow ◽

Animal Populations ◽

Barn Swallows

Animal populations are often limited by food availability, particularly during the breeding season. In birds, food limitation can impact several components of the reproductive cycle, including the timing of reproduction and reproductive output. Barn Swallows (Hirundo rustica Linnaeus, 1758) have experienced a population decline over the past 40 years in North America that is thought to be related to changes in prey availability. We monitored Barn Swallow reproductive behaviour and prey availability throughout two breeding seasons at 10 sites in Ontario, Canada, to test the hypothesis that limited prey availability during the breeding season affected reproductive behaviour. We found no relationship between food availability and number of eggs laid or number of young fledged. Neither did we observe higher rates of second brooding or more pairs nesting at breeding sites with higher food availability. Barn Swallows did not time their reproductive effort to maximize prey availability during the nesting period, but any mismatch in phenology of prey and bird reproduction at a breeding site was not associated with lower reproductive success. The results of this study did not support our hypothesis and suggest that Barn Swallow reproductive behaviour was not negatively affected by limited prey availability on the breeding grounds.

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Evaluation of the dark field method for large association of spread DNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081814 ◽

1978 ◽

Vol 36 (2) ◽

pp. 190-191

Author(s):

Douglas C. Barker

Keyword(s):

Electron Microscopy ◽

Molecular Weight ◽

Mitochondrial Dna ◽

Extraction Method ◽

Field Method ◽

Dark Field ◽

Kinetoplast Dna ◽

Field Electron ◽

Field Electron Microscopy ◽

Dark Field Electron

A number of satisfactory methods are available for the electron microscopy of nicleic acids. These methods concentrated on fragments of nuclear, viral and mitochondrial DNA less than 50 megadaltons, on denaturation and heteroduplex mapping (Davies et al 1971) or on the interaction between proteins and DNA (Brack and Delain 1975). Less attention has been paid to the experimental criteria necessary for spreading and visualisation by dark field electron microscopy of large intact issociations of DNA. This communication will report on those criteria in relation to the ultrastructure of the (approx. 1 x 10-14g) DNA component of the kinetoplast from Trypanosomes. An extraction method has been developed to eliminate native endonucleases and nuclear contamination and to isolate the kinetoplast DNA (KDNA) as a compact network of high molecular weight. In collaboration with Dr. Ch. Brack (Basel [nstitute of Immunology), we studied the conditions necessary to prepare this KDNA Tor dark field electron microscopy using the microdrop spreading technique.

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A Many-Beam Technique for Enhanced Resolution of Partial Dislocations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096485 ◽

1972 ◽

Vol 30 ◽

pp. 646-647

Author(s):

J. M. Oblak ◽

B. H. Kear

Keyword(s):

Phase Shift ◽

Field Method ◽

Dark Field ◽

Bright Field ◽

Field Technique ◽

Weak Beam ◽

Partial Dislocations ◽

Enhanced Resolution ◽

Nickel Base ◽

Beam Technique

The “weak-beam” and systematic many-beam techniques are the currently available methods for resolution of closely spaced dislocations or other inhomogeneities imaged through strain contrast. The former is a dark field technique and image intensities are usually very weak. The latter is a bright field technique, but generally use of a high voltage instrument is required. In what follows a bright field method for obtaining enhanced resolution of partial dislocations at 100 KV accelerating potential will be described.A brief discussion of an application will first be given. A study of intermediate temperature creep processes in commercial nickel-base alloys strengthened by the Ll2 Ni3 Al γ precipitate has suggested that partial dislocations such as those labelled 1 and 2 in Fig. 1(a) are in reality composed of two closely spaced a/6 <112> Shockley partials. Stacking fault contrast, when present, tends to obscure resolution of the partials; thus, conditions for resolution must be chosen such that the phase shift at the fault is 0 or a multiple of 2π.

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