Parasitism by Brown-headed Cowbirds and productivity of House Finch hosts

1998 ◽  
Vol 76 (9) ◽  
pp. 1714-1721 ◽  
Author(s):  
Daniel R Kozlovic
Keyword(s):  
Clutch Size ◽  
Reproductive Output ◽  
Molothrus Ater ◽  
Carpodacus Mexicanus ◽  
House Finch ◽  
House Finches ◽  
Cowbird Parasitism ◽  
The Mean ◽  
Egg Removal ◽  
Established Population

The effect of parasitism by Brown-headed Cowbirds (Molothrus ater) on the reproductive success of a recently established population of House Finches (Carpodacus mexicanus) was studied at St. Catharines, Ontario, during 1983-1985. House Finches began to colonize Ontario in 1972 and breeding was first observed there in 1978. Cowbirds laid in 40.2% of House Finch nests and parasitism was most prevalent during the peak of House Finch nesting. Clutches initiated early in the season were free of cowbird eggs. Most (76%) House Finch nests were parasitized within 2 days after the first House Finch egg was laid. Parasitized House Finch nests contained 1-3 cowbird eggs and the mean number of cowbird eggs per parasitized nest was 1.30. Frequency of multiple parasitism was 24.2% and the number of cowbird eggs per nest was not significantly different from a truncated Poisson distribution. Cowbird parasitism depressed House Finch clutch size and number of hatchlings and fledglings, but the proportion of surviving eggs in parasitized nests that yielded hatchlings and fledglings was not influenced by parasitism. Overall growth of House Finch nestlings did not differ significantly between parasitized and unparasitized nests. Thus, House Finches were able to successfully rear most of their young irrespective of parasitism. The decrease in reproductive output of House Finches was mainly due to egg removal by cowbirds, which effectively reduced the clutch size of parasitized nests by about 1 House Finch egg.

scholarly journals Dynamics of Conjunctivitis and Mycoplasma Gallisepticum Infections in House Finches

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 327-333 ◽  
Author(s):  
Barry K. Hartup ◽  
Jean M. Bickal ◽  
Andre A. Dhondt ◽  
David H. Ley ◽  
George V. Kollias
Keyword(s):  
Breeding Season ◽  
Annual Variation ◽  
Seasonal Fluctuation ◽  
Host Density ◽  
Mycoplasma Gallisepticum ◽  
Disease Prevalence ◽  
Significant Decline ◽  
Carpodacus Mexicanus ◽  
House Finch ◽  
House Finches

Abstract Conjunctivitis, an infectious disease caused by Mycoplasma gallisepticum (MG), has produced a significant decline in eastern House Finches (Carpodacus mexicanus) of North America. In this paper, we present findings from two complementary studies designed to clarify annual and seasonal trends of MG infections in House Finches from the northeastern United States. The first was a field study of House Finches common to urban and residential habitat from Mercer County, New Jersey. We documented conjunctivitis in 11% (188/1,651) of the birds examined. Conjunctivitis prevalence in House Finches ranged from 0 to 43% per month, and exhibited marked seasonal fluctuation (elevations during fall and winter months and lower disease prevalence during the breeding season). There was excellent intermethod agreement on disease prevalence when measured by either presence of physical signs (conjunctivitis) or MG infection (kappa = 0.75). During the peak of the breeding season (April through June), conjunctivitis was present in a greater proportion of males lacking a cloacal protuberance than males with a cloacal protuberance (P < 0.01), but was similar between breeding and nonbreeding females. The second study, a volunteer survey, revealed the proportion of northeastern U.S. monitoring sites with at least one diseased House Finch each month ranged from a peak of 59% (August 1995) to a minimum of 12% (July 1999). Subsequent to the epidemic peak of disease in 1995, a series of recurring cycles occurred, with elevations in those proportions noted in late fall and winter and minima during the breeding season. Mycoplasmal conjunctivitis now appears endemic among House Finches of that region and demonstrates dynamics consistent with annual variation in host density.

scholarly journals Effects of Vegetation, Interspecific Competition, and Brood Parasitism on Golden-Winged Warbler (Vermivora Chrysoptera) Nesting Success

The Auk ◽  
2003 ◽  
Vol 120 (1) ◽  
pp. 138-144
Author(s):  
John L. Confer ◽  
Jeffery L. Larkin ◽  
Paul E. Allen
Keyword(s):  
New York ◽  
Clutch Size ◽  
Brood Size ◽  
Molothrus Ater ◽  
Tree Cover ◽  
North Central ◽  
Vermivora Chrysoptera ◽  
Central New York ◽  
Negative Effect ◽  
Cowbird Parasitism

Abstract The recent decline of Golden-winged Warblers (Vermivora chrysoptera) correlates with the loss of suitable nesting habitat, range expansion by Blue-winged Warblers (V. pinus), and eastward expansion of Brown-headed Cowbirds (Molothrus ater). Multivariate statistics were used to examine effects of those factors on Golden-winged Warbler reproduction in north central New York. Herb and shrub cover were positively correlated with clutch size. Blue-winged Warbler proximity was negatively correlated with Golden-winged Warbler clutch size. Tree cover and perhaps herb cover, after adjusting for brood size, correlated with a reduced number of Golden-winged Warbler fledglings. Herbaceous cover correlated with a greater number of cowbird eggs in Golden-winged Warbler nests. Cowbird parasitism correlated with a reduction in the number of Golden-winged Warbler eggs incubated and proportion of incubated eggs that hatched. However, cowbird parasitism, after adjusting for brood size, did not significantly affect nestling success rate. Cowbirds parasitized 30% of Golden-winged Warbler nests, which reduced the number of Golden-winged Warblers fledged by ∼17%. Average herb and tree cover values were 69 and 22 in Golden-winged Warbler territories and 60 and 23 in Blue-winged Warbler territories, respectively, with herb cover significantly greater for Golden-winged Warblers. Territories in the earliest stages of succession used by Golden-winged Warblers supported larger clutches and a reduction in the strong, negative effect of Blue-winged Warbler proximity and an increase in the negative effect correlated with cowbirds, if cowbirds were locally abundant.

Syllable and Song Sharing in a Recently Established Population of House Finches (Carpodacus mexicanus)

The Auk ◽  
2009 ◽  
Vol 126 (4) ◽  
pp. 823-830 ◽  
Author(s):  
Todd T. Tracy ◽  
Hannah J. Zasadny ◽  
John G. Erickson ◽  
Jeremy L. Siemers
Keyword(s):  
Carpodacus Mexicanus ◽  
House Finches ◽  
Song Sharing ◽  
Established Population

Age, sex, and season affect the risk of mycoplasmal conjunctivitis in a southeastern house finch population

2004 ◽  
Vol 82 (5) ◽  
pp. 755-763 ◽  
Author(s):  
Sonia Altizer ◽  
Andrew K Davis ◽  
Katherine C Cook ◽  
John J Cherry
Keyword(s):  
North America ◽  
Clinical Signs ◽  
Host Susceptibility ◽  
Eye Disease ◽  
Carpodacus Mexicanus ◽  
House Finch ◽  
House Finches ◽  
Factors Associated ◽  
High Prevalence ◽  
Severe Infections

House finches (Carpodacus mexicanus (Muller, 1776)) in eastern North America have been affected by annual epidemics of an eye disease caused by the bacterium Mycoplasma gallisepticum since 1994. To identify factors associated with seasonal changes in prevalence and variation in host susceptibility, we monitored mycoplasmal conjunctivitis among wild house finches in a region of high prevalence in southeastern North America. We captured 888 birds between August 2001 and December 2003 and observed seasonal outbreaks characterized by rapid increases in prevalence from August to October each year. During periods of high prevalence, infection probability was significantly higher among juveniles than adults, and the severity of conjunctivitis among juvenile females was greater than for any other host category. We found no evidence linking moulting status to elevated infection risk among adult birds. Finally, house finches with conjunctivitis were in poorer condition than birds with no clinical signs of infection, particularly among those with severe infections. Results from this study are consistent with recent reports of seasonal and regional variation in mycoplasmal conjunctivitis and suggest that annual changes in host reproduction, behaviour, and age structure might be important determinants of the timing and magnitude of local epidemics.

Electrically Elicited Vocalization From the Brain of the House Finch (Carpodacus Mexicanus)

Behaviour ◽  
1977 ◽  
Vol 60 (1-2) ◽  
pp. 75-97 ◽  
Author(s):  
Richard A. Epro
Keyword(s):  
Local Anesthetic ◽  
Carpodacus Mexicanus ◽  
House Finch ◽  
Male And Female ◽  
House Finches ◽  
Call Type ◽  
Anatomical Localization ◽  
Males And Females ◽  
The Brain

AbstractVocalizations were electrically elicited from the brains of thirty-eight male and female house finches (Carpodacus mexicanus) using acute procedures and local anesthetic. Nine types of call notes were produced including notes which sounded like song elements, but complete normal song was never evoked. Vocalizations could be electrically elicited from all parts of the brain except the cerebellum, but the widest variety of calls and the points yielding vocalizations at the lowest threshold were located in the midbrain around the nucleus mesencephalicus lateralis pars dorsalis. Precise anatomical localization of call type was not found and all calls were elicited from both males and females.

scholarly journals How do Brown-Headed Cowbirds (Molothrus Ater) CAUSE NEST FAILURES IN SONG SPARROWS (MELOSPIZA MELODIA)? A REMOVAL EXPERIMENT

The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 772-783
Author(s):  
James N. M. Smith ◽  
Mary J. Taitt ◽  
Liana Zanette ◽  
Isla H. Myers-Smith
Keyword(s):  
Clutch Size ◽  
Breeding Season ◽  
Molothrus Ater ◽  
Melospiza Melodia ◽  
Removal Experiment ◽  
Song Sparrow ◽  
Failure Rates ◽  
Nest Failure ◽  
Song Sparrows ◽  
Egg Removal

Abstract A removal experiment was conducted to measure how much and by what mechanisms brood parasitic Brown-headed Cowbirds (Molothrus ater) cause nest failures in a commonly used host, the Song Sparrow (Melospiza melodia). When numbers of female cowbirds were reduced experimentally, nest failures fell from 65.0% (n = 663 nests) to 49.9% (n = 331). Cowbird reduction reduced the frequency of nest failure to one-third of control levels in Song Sparrows during the last 80 days of the sparrow's breeding season, the period when most parasitic laying took place. Cowbird reduction decreased nest failures strongly at the egg stage, and weakly at the nestling stage. Daily nest-failure rates were independent of whether or not a nest was parasitized by cowbirds. Two hypotheses were tested to explain how cowbirds cause host nests to fail: first, egg removal by female cowbirds lowers clutch size below a threshold where the host deserts; second, cowbirds cause host nests to fail by destroying entire clutches or broods. In support of the first hypothesis, desertion following parasitism and egg removal was less frequent when cowbird numbers were reduced (8.9% of n = 158 nests) than for unmanipulated controls (16.5% of n = 424 nests). In support of the second hypothesis, there were fewer cases where young were killed in the nest, or found dead near it, after cowbird numbers were reduced (2.5% of 158 nests) than in controls (4.7% of 424 control nests). In contrast, proportions of nests that failed after the disappearance of all eggs, young, or both, and after unparasitized clutches were deserted, increased when cowbird numbers were reduced. Although our study supports both hypotheses, cowbird-induced desertion had a greater effect on nest failure rates than did cowbird predation. Our study suggests that cowbird removal programs are likely to benefit commonly used and endangered hosts by reducing rates of nest failure.

scholarly journals Brown-headed Cowbird, Molothrus ater, Parasitism and Abundance in the Northern Great Plains

2007 ◽  
Vol 121 (3) ◽  
pp. 239 ◽  
Author(s):  
Lawrence D. Igl ◽  
Douglas H. Johnson
Keyword(s):  
Great Plains ◽  
Molothrus Ater ◽  
Bird Community ◽  
Northern Great Plains ◽  
Breeding Bird ◽  
Host Parasite Interactions ◽  
Parasitism Rates ◽  
Cowbird Parasitism ◽  
The Mean ◽  
Host Parasite

The Brown-headed Cowbird (Molothrus ater) reaches its highest abundance in the northern Great Plains, but much of our understanding of cowbird ecology and host-parasite interactions comes from areas outside of this region. We examine cowbird brood parasitism and densities during two studies of breeding birds in the northern Great Plains during 1990–2006. We found 2649 active nests of 75 species, including 746 nonpasserine nests and 1902 passerine nests. Overall, <1% of nonpasserine nests and 25% of passerine nests were parasitized by Brown-headed Cowbirds. Although the overall frequency of cowbird parasitism in passerine nests in these two studies is considered moderate, the frequency of multiple parasitism among parasitized nests was heavy (nearly 50%). The mean number of cowbird eggs per parasitized passerine nest was 1.9 ± 1.2 (SD; range = 1–8 cowbird eggs). The parasitism rates were 9.5% for passerines that typically nest in habitats characterized by woody vegetation, 16.4% for grassland-nesting passerines, 4.7% for passerines known to consistently eject cowbird eggs, and 28.2% for passerines that usually accept cowbird eggs. The Red-winged Blackbird (Agelaius phoeniceus) was the most commonly parasitized species (43.1% parasitism, 49.6% multiple parasitism, 71.2% of all cases of parasitism). Passerine nests found within areas of higher female cowbird abundance experienced higher frequencies of cowbird parasitism than those found in areas of lower female cowbird abundance. Densities of female cowbirds were positively related to densities and richness of other birds in the breeding bird community.

Nest mites (Pellonyssus reedi) and the reproductive biology of the house finch (Carpodacus mexicanus)

2000 ◽  
Vol 78 (12) ◽  
pp. 2126-2133 ◽  
Author(s):  
Andrew M Stoehr ◽  
Paul M Nolan ◽  
Geoffrey E Hill ◽  
Kevin J McGraw
Keyword(s):  
Reproductive Biology ◽  
Carpodacus Mexicanus ◽  
House Finch ◽  
East Central ◽  
House Finches ◽  
Male Plumage ◽  
Initial Appearance ◽  
Almost All ◽  
Mite Infestations ◽  
Male House

We investigated the effects of a hematophagous nestling mite (Pellonyssus reedi, Acari: Macronyssidae) on the reproductive biology of the house finch (Carpodacus mexicanus) in east-central Alabama, U.S.A. Mites were absent from nests for the first half of the breeding season, but after their initial appearance they increased in number and were present in almost all nests. High nest-mite levels were associated with decreased nestling mass and hematocrit, but not with decreased nestling tarsus length. Experimental elimination of mites from some nests confirmed that the effects observed were mite-induced, not seasonal. The plumage colour of breeding adult male house finches was not correlated with nest-mite levels, nor did it appear that redder males' offspring suffered less from the effects of mites. Adult house finches fed nestlings from highly parasitized nests less often than those from nests with few or no mites. It appears unlikely that mites are directly involved in the sexual selection of bright male plumage coloration in this population of house finches. However, it is known that early-nesting females preferentially pair with redder males, therefore the benefit of nesting early and avoiding mite infestations is greater for redder male house finches.

scholarly journals First Case of Mycoplasma Gallisepticum Infection in the Western Range of The House Finch (Carpodacus Mexicanus)

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 528-530 ◽  
Author(s):  
Renee A. Duckworth ◽  
Alexander V. Badyaev ◽  
Kristy L. Farmer ◽  
Geoffrey E. Hill ◽  
Sharon R. Roberts
Keyword(s):  
Mycoplasma Gallisepticum ◽  
Western Montana ◽  
Carpodacus Mexicanus ◽  
Close Monitoring ◽  
House Finch ◽  
Eastern United States ◽  
House Finches ◽  
First Case ◽  
Evolution Of Resistance ◽  
Insight Into

Abstract We report the first case of mycoplasmosis in the western range of the House Finch (Carpodacus mexicanus). This disease originated in the eastern United States and has been previously documented only in eastern introduced House Finch populations where it reached epizootic proportions causing extensive and widespread mortality. Documentation of this dis-ease in western Montana suggests that previously disjunct eastern and western populations of House Finches are now mixing in the northern part of their range. More importantly, as native House Finches are highly susceptible to this novel pathogen, western populations may now be at risk of high mortality, similar to that experienced by non-native eastern populations. Close monitoring of this disease in the western part of the House Finch range will provide important insight into the dynamics of the emerging disease and evolution of resistance to the pathogen.

scholarly journals Isolation of a Poxvirus from a House Finch, Carpodacus mexicanus (Müller)

1986 ◽  
Vol 22 (3) ◽  
pp. 420-422 ◽  
Author(s):  
Douglas E. Docherty ◽  
Renee I. Romaine Long
Keyword(s):  
Carpodacus Mexicanus ◽  
House Finch
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