Topic
Diving bird
About: Diving bird is a research topic. Over the lifetime, 24 publications have been published within this topic receiving 821 citations.
Papers
TL;DR: The energetic costs of replacing flight remiges in female eiders are substantial, although this is not associated with any change in foraging effort, which suggests that female Common Eiders lose mass during wing molt.
Abstract: Although the replacement of feathers apparently represents the major event of somatic production in the annual cycle of wild birds, knowledge about the energetics of molt has always been hampered by logistical and technical difficulties, which are exacerbated by the fact that birds are able to compensate behaviorally to buffer any variation in energy demand. During wing molt, sea ducks (Mergini) and other diving birds lose all of their wing feathers at once, leading to a period of temporary flightlessness of variable duration, a condition that considerably restricts their movements and increases the probability of predation. In the present study, we present the first results aimed at quantifying the duration of flightlessness, energy expenditure, and foraging effort during molt of a wing-propelled diving bird, the Common Eider (Somateria mollissima). Data loggers were implanted in the body cavity of 13 females to record heart rate and hydrostatic pressure (depth) every two seconds for a period of 220 days. Flight frequency and duration were assessed from elevated and constant heart rate, and the absence of flight was used to quantify the duration of flightlessness, which lasted, on average, 36 ± 8 days (mean ± SD). Using a period of four weeks before and four weeks after the flightless period, we found that dive depth (ranging from 1 to 2 m, on average) and daily diving time did not vary during the course of the study. Daily metabolic rate increased by 9%, and resting metabolic rate by 12% from the pre-molt period to the flightless period and remained high during the post-molt period. This study indicates that the energetic costs of replacing flight remiges in female eiders are substantial, although this is not associated with any change in foraging effort, which suggests that female Common Eiders lose mass during wing molt. Finally, estimates of energy savings associated with the total absence of flights during wing molt represent 6% of daily metabolic rate or 14% of resting metabolic rate. This finding contrasts with the classical view that little or no benefit is associated with a flightless condition. We suggest that such energy savings may have favored the evolution of temporary flightlessness in diving birds.
93 citations
TL;DR: Birds appeared to maintain the duration and the maximum strength of power stroke and thus optimize muscle contraction efficiency during the descent, ascent and bottom phases of a foot-propelled diving bird, the European shag Phalacrocorax aristotelis in the wild.
Abstract: SUMMARY Bottom-feeding, breath-hold divers would be expected to minimize transit
time between the surface and foraging depth, thus maximizing the opportunities
for prey capture during the bottom phase of the dive. To achieve this they can
potentially adjust a variety of dive parameters, including dive angle and swim
speed. However, because of predictable changes in buoyancy with depth,
individuals would also be expected to adjust dive behavior according to dive
depth. To test these predictions we deployed miniature, dorsally attached
data-loggers that recorded surge and heave accelerations at 64 Hz to obtain
the first detailed measurements of a foot-propelled diving bird, the European
shag Phalacrocorax aristotelis , in the wild. The results were used to
investigate biomechanical changes during the descent, ascent and bottom phases
for dives varying between 7 m and 43 m deep. Shags descended and ascended
almost vertically (60–90° relative to the sea surface). During
descent, swim speed varied between 1.2–1.8 m s –1 and
the frequency of the foot stroke used for propulsion decreased significantly
with depth, mainly due to a fivefold increase in the duration of the glide
between strokes. Birds appeared to maintain the duration and the maximum
strength of power stroke and thus optimize muscle contraction efficiency.
80 citations
TL;DR: DLW was used to estimate the metabolic rate of the diving tufted duck and the derived estimate was compared with the value obtained by direct respirometry, and care should be exercised in interpreting measurements derived from DLW for these animals.
Abstract: 1. The doubly labelled water (DLW) technique has been used to estimate the rate of energy expenditure of many species of free-living birds including some that dive. The technique, however, has never been validated in an actively diving bird. 2. DLW was used to estimate the metabolic rate of the diving tufted duck and the derived estimate was compared with the value obtained by direct respirometry. All the equations used to calculate the energy expenditure from DLW produced estimates for individual birds with large ranges of errors. Even the most accurate equation, S4 (Speakman 1993), underestimated oxygen consumption by an average of 15.6%. The range of errors for that equation (− 83 to + 67%) shows that in the diving tufted duck, the DLW technique has a reduced precision3. This reduced precision is probably due to the high water flux measured. As a high water turnover is likely to be a consistent feature of many diving and swimming birds and mammals, care should be exercised in interpreting measurements derived from DLW for these animals4. Heart rate, used as another indicator of metabolic rate, was also monitored in four of the birds. Although there was again a wide range of individual errors (− 38 to + 71%), the mean estimate was not significantly different from those derived from DLW and direct respirometry
80 citations
TL;DR: It is suggested that the divergence of time and energy costs with dive depth has implications for the measurement of dive efficiency across diverse diving taxa.
Abstract: Animals may forage using different currencies depending on whether time minimization or energy maximization is more pertinent at the time. Assessment of net energy acquisition requires detailed information on instantaneous activity-specific power use, which varies according to animal performance, being influenced, for example, by speed and prey loading, and which has not been measured before in wild animals. We used a new proxy for instantaneous energy expenditure (overall dynamic body acceleration), to quantify foraging effort in a model species, the imperial shag Phalacrocorax atriceps, during diving. Power costs varied nonlinearly with depth exploited owing to depth-related buoyancy. Consequently, solutions for maximizing the gross rate of gain and energetic efficiency differed for dives to any given depth. Dive effort in free-ranging imperial shags measured during the breeding season was consistent with a strategy to maximize the gross rate of energy gain. We suggest that the divergence of time and energy costs with dive depth has implications for the measurement of dive efficiency across diverse diving taxa.
76 citations
TL;DR: In this paper, the authors addressed the issue of bird bycatch in set-nets in the southern Baltic Sea by assessing the vulnerability of diving birds to drowning by developing a vulnerability index based on weighted bird abundance, providing information on set-net fishing activities, and using a spatial overlap approach to indicate the potential conflicts between diving birds and fishing activities.
Abstract: We addressed the issue of bird bycatch in set-nets in the southern Baltic Sea by (i) assessing the vulnerability of diving birds to drowning by developing a vulnerability index based on weighted bird abundance, (ii) providing information on set-net fishing activities, and (iii) using a spatial overlap approach to indicate the potential conflicts between diving birds and fishing activities. Birds and fisheries concentrated in the same areas. Vulnerability and potential conflict were highest during winter and spring in coastal waters and around shallow offshore grounds. Local bycatch studies validated the usefulness of our approach, which can provide a valuable tool for conservation purposes. Although the conflict analysis outlined the current extent of overlap between birds and fisheries, the vulnerability index indicated important areas and periods in terms of diving bird abundance, irrespective of fisheries, and enabled the development of appropriate conservation and management options. A suite of measures including temporal or spatial restrictions can be derived, despite a scarcity of real data for bycatch rates. This approach is particularly useful for assessing impacts that are difficult to monitor and where mortality cannot be properly addressed, as in artisanal gillnet fisheries. It is also generally applicable to any marine area or species worldwide.
42 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2019 | 1 |
| 2015 | 1 |
| 2014 | 2 |
| 2013 | 1 |
| 2012 | 4 |