Effect of ectoparasitism by larvae of the blow fly Protocalliphora parorum (Diptera: Calliphoridae) on nestling House Wrens, Troglodytes aedon

1991 ◽  
Vol 69 (6) ◽  
pp. 1441-1446 ◽  
Author(s):  
L. Scott Johnson ◽  
Marjorie D. Eastman ◽  
L. Henry Kermott

We investigated the effect of ectoparasitism by hematophagous larvae of the blow fly Protocalliphora parorum on nestling House Wrens (Troglodytes aedon) over 2 years in north-central Wyoming, U.S.A. Approximately 85% of wren nests contained P. parorum larvae. Mean parasite load was approximately 10 larvae per nestling. Nestling tarsus length, primary feather length, and hematocrit measured just before fledging did not differ significantly with parasite load. However, parasitized birds weighed approximately 8% more than unparasitized birds just prior to fledging. Parasites possibly delay the recession in weight that normally occurs as tissues mature late in the nestling stage. Delayed development may result in increased nestling or fledgling mortality.

1989 ◽  
Vol 67 (10) ◽  
pp. 2358-2362 ◽  
Author(s):  
Marjorie D. Eastman ◽  
L. Scott Johnson ◽  
L. Henry Kermott

We provide the first detailed information concerning ectoparasitism of nestling birds by larvae of the blow fly, Protocalliphora braueri Hendel. This species is unusual among Protocalliphora because its larvae cause a subcutaneous myiasis in small birds. We examined the pattern of infestation, and the effect of parasites on nestling survival and body size at fledging in a population of House Wrens, Troglodytes aedon. Twenty-five of 71 nests (35%) in the population were infested. Infested nestlings hosted an average of five larvae each. Myiases occurred in virtually all parts of nestling bodies, and larvae were visible on hosts for approximately 3 days. Parasitism did not appear to affect nestling survival if larvae appeared after the nestlings were approximately 6 days old. Some young infested at ages younger than this appeared to die as a result of parasitism, but infestation at these ages was rare (only 12% of nests). Comparison with other studies of dipteran ectoparasitism suggests that in most cases, parasite loads in our population are generally too low to have any significant effect on nestling survival. We also found no relationship between the intensity of parasitism and the tarsus size of nestlings at the time that they fledge, as measured by tarsus length.


The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 183-187 ◽  
Author(s):  
Brian L. Morrison ◽  
L. Scott Johnson

Abstract This study asked whether parent House Wrens (Troglodytes aedon) in a Wyoming population increased rates of food delivery to broods parasitized by hematophagous blow fly larvae and mites. We observed no significant difference in rates at which pairs fed nestlings at nests with naturally heavy infestations of fly larvae (6–19 larvae per nestling) and nests in which nestling exposure to larvae was experimentally eliminated or severely reduced (0–2 larvae per nestling). The apparent failure of parents to compensate nestlings for resources lost to parasites may, in part, explain the reduced rates of mass gain by parasitized nestlings that we observed and the presence of reduced hemoglobin levels in parasitized nestlings documented in a companion study. Parasitized nestlings may be too weak or anemic to intensify begging activity which would alert parents to their increased need for food. Alimentación de Polluelos de Troglodytes aedon Afectada por Ectoparásitos Hematófagos: Una Prueba de la Hipótesis de Compensación Parental Resumen. Nos preguntamos si los individuos parentales de Troglodytes aedon de una población de Wyoming aumentan las tasas de alimentación sobre polluelos parasitados por ácaros y larvas de moscas hematófagas. No observamos diferencias significativas en la tasa a la cual las parejas alimentaron a los polluelos entre nidos altamente infectados naturalmente por la larva de la mosca (6–19 larvas por polluelo) y nidos en que la exposición a las larvas fue eliminada o severamente reducida experimentalmente (0–2 larvas por polluelo). En parte, la aparente falta de compensación por parte de los padres sobre la pérdida de recursos de los polluelos infectados puede explicar sus bajas tasas de ganancia de peso y los niveles reducidos de hemoglobina documentados en un estudio asociado al presente. Los polluelos parasitados probablemente se encuentran muy débiles o anémicos como para intensificar la actividad de reclamo lo que alertaría a los padres sobre su mayor necesidad de alimento.


2021 ◽  
pp. 175815592098715
Author(s):  
José Carrillo-Ortiz ◽  
Santi Guallar ◽  
Jessica Martínez-Vargas ◽  
Javier Quesada

The methods used to preserve bird skins in museums have a potentially crucial impact on the feasibility and use of these specimens as a source of biological knowledge, although this subject is rarely broached. Study skins of birds are usually prepared with folded wings and straight legs to facilitate storage in the collection; yet, this method can hamper the measurement and examination of certain important features such as wing-feather moult. To make consultation easier for ornithologists, alternative preparation methods such as the splitting of wings and tarsi from the rest of the animal have been proposed by curators. Our aim was to study whether or not preparing bird specimens with spread limbs makes consultation simpler. First, we used two different methods to prepare two specimens each of two common European passerine species: (1) ‘traditional’ (folded wings and straight tarsi) and (2) ‘spread’ (limbs spread on one side of the body). Then, we asked 22 experienced ornithologists to identify moult limits and take three biometric measurements (wing chord, length of the third primary feather and tarsus length) from all four specimens. Subsequently, we asked which preparation method they preferred for obtaining data. The ‘spread’ preparation was preferred for moult, third primary feather length and tarsus length, whilst the ‘traditional’ preparation was preferred for wing chord. Data obtained from the folded and spread preparations were very highly repeatable within each method but only moderately to highly repeatable between methods. One of the handicaps with the ‘spread’ preparation is the increase in storage space required, a factor that should be taken into account before it is employed. Nevertheless, this specimen preparation technique can greatly facilitate consultation and therefore improve the scientific value of ornithological collections.


Behaviour ◽  
1996 ◽  
Vol 133 (5-6) ◽  
pp. 357-366 ◽  
Author(s):  
William A. Searcy ◽  
L. Scott Johnson

AbstractThis study tested the hypothesis that the song of male birds can function to attract mates. At 11 different locations on our Wyoming study area, we broadcast the song of male house wrens (Troglodytes aedon) from a loudspeaker mounted next to an empty nest box in an unoccupied wren territory. The number of female wrens attracted to the 'speaker box' was compared to the number visiting a silent, control box on another, unoccupied territory nearby. Females visited speaker boxes at a significantly higher rate than they visited control boxes. Ten females visited speaker boxes in six different trials during periods when no male was associated with either the speaker or control box (total time = 45.5 h; visit rate = 0.22/h). In contrast, only one female visited a control box during these same periods (= 0.02 visits/h), and she did so after first visiting the speaker box. Two females visited the speaker box simultaneously in some trials and chasing or fighting always ensued. Many females showed signs of settling permanently at speaker boxes, remaining at speaker boxes from their arrival to the end of the trial (> 5 h in two cases), and most began constructing nests in boxes, despite the absence of a male. In summary, this study provides strong experimental evidence that the song of male house wrens can function to attract mates for breeding.


2019 ◽  
Vol 97 (1) ◽  
pp. 50-56
Author(s):  
C.L. Gable ◽  
T.J. Underwood ◽  
G.P. Setliff

House Wrens (Troglodytes aedon Vieillot, 1809) regularly add spider egg cases (Arachnida: Araneae) to their nests, which may be an example of heterospecific cleaning. This behavior involves one animal employing another to remove parasites from their nests. In House Wren nests, juvenile spiders hatching from egg cases may facilitate the reduction of mites that feed on nestlings. We tested this ectoparasite reduction hypothesis by monitoring House Wren nests for spider egg cases and by collecting completed nests to compare the number of spider egg cases and Dermanyssus hirundinis (Hermann, 1804) mites. No significant relationship was found between the number of spider egg cases and number of D. hirundinis mites in nests. We also found no significant relationship between the number of D. hirundinis mites in nests and the body condition of nestlings. Finally, no significant difference was found between the number of D. hirundinis mites in early versus late season nests, but significantly more spider egg cases were added to late season nests. Of a subsample of spider egg cases dissected, we found that 28% contained spider eggs or embryos. We also identified three species of juvenile spiders from House Wren nests using DNA barcoding. Overall, we found no evidence that spider egg cases reduce the number of D. hirundinis mites or engender better quality offspring in House Wren nests.


The Auk ◽  
1988 ◽  
Vol 105 (3) ◽  
pp. 480-491 ◽  
Author(s):  
Nancy E. Drilling ◽  
Charles F. Thompson

Abstract We studied the natal and breeding dispersal of yearling and adult House Wrens (Troglodytes aedon) for 7 yr in central Illinois. The forested study areas contained 910 identical nest boxes placed in a grid pattern. On average 38.1% (n = 643) of the adult males and 23.3% (n = 1,468) of the adult females present in one year returned the next; 2.8% (n = 6,299) of the nestlings that survived to leave the nest returned each year. Adult male (median distance = 67 m) and adult female (median = 134 m) breeding dispersal was less than yearling male (median = 607.5 m) and yearling female (median = 674 m) natal dispersal. Females that returned had produced more offspring the previous season than had nonreturning females, and females that successfully produced at least one chick in their last nesting attempt of the previous season moved shorter distances than did unsuccessful females. There were, however, no consistent differences between returning and nonreturning females in two other measures of reproductive success. Females that were unsuccessful in their last breeding attempt of the previous year were more likely to be successful in their next attempt if they moved two or more territories than if they did not move. Reproductive success did not affect the likelihood that a male would return nor the distance that he moved. The success of subsequent nesting attempts by males was also not related to the distance moved. Inbreeding avoidance may explain differences between breeding and natal dispersal, but it does not explain the lack of difference in dispersal of yearling females and males. Differences between adult and yearling dispersal are best explained by advantages accruing to adults that remain near former breeding sites and by the necessity for yearlings to move farther because of their late return from the wintering grounds. The advantages for adults to reoccupy previous breeding sites are counterbalanced, especially in females, by advantages associated with moving after breeding failure.


2008 ◽  
Vol 17 (16) ◽  
pp. 3697-3706 ◽  
Author(s):  
ANNA M.  FORSMAN ◽  
LAURA A.  VOGEL ◽  
SCOTT K.  SAKALUK ◽  
BONNIE G.  JOHNSON ◽  
BRIAN S.  MASTERS ◽  
...  

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