Common Goldeneye Bucephala Clangula Research Articles

British Ornithologists’ Union Records Committee: 37th Report (October 2008)

British Ornithologists’ Union Records Committee: 37th Report (October 2008)

Common Goldeneye Breeding in the Eastern Canadian Boreal Forest: Factors Affecting Productivity Estimates

Abstract We conducted multiple Common Goldeneye (Bucephala clangula) aerial surveys between 1 May and 31 July 2004 and 2005 on the Peribonka River, where a new hydroelectric reservoir will be created in 2007. We also conducted single pair and brood surveys on randomly chosen 5 × 5-km plots on the River drainage basin. Objectives were to assess the validity of the impact assessment surveys of 2002, examine the variation in pair and brood numbers, and determine recruitment and habitat characteristics related to productivity. During both years, the number of indicated breeding pairs (IBPs) declined steadily through May, whereas the social index (paired males/lone males) remained stable, declining only when few IBPs were located. However, backdated number of paired and lone males from observed broods suggested that the number of pairs remained maximal and constant during a three-week period centered on the fourth week of May in 2004 and the second week of May in 2005. IBP density (IBPs/10 km of shoreline) was...

Survival of common goldeneye Bucephala clangula ducklings in relation to weather, timing of breeding, brood size, and female condition

Survival of common goldeneye Bucephala clangula ducklings in relation to weather, timing of breeding, brood size, and female condition

Survival of common goldeneye Bucephala clangula ducklings in relation to weather, timing of breeding, brood size, and female condition

The survival of common goldeneye Bucephala clangula ducklings during their first week of life was studied in relation to hatching date, brood size, female condition, and weather (temperature and precipitation) during the first week post‐hatch by using data from radio‐marked females and their broods. Also, age‐specific variation in the survival of the young was determined until fledging (over 50 d of age). Survival was lowest in the first week after hatching. Hatching date, brood size, and first week temperature and precipitation were poor predictors of duckling survival during the first week after nest exodus. Instead, the ducklings of females in a better body condition survived better in their first week of life. The results suggest that weather does not have a direct effect on downy ducklings’ survival, but the condition of the female seems to be an important determinant of the survival of common goldeneye ducklings.

Brood rearing costs affect future reproduction in the precocial common goldeneye Bucephala clangula

Life‐history theory assumes a trade‐off between current reproductive effort and future reproductive success. There are a large number of studies demonstrating reproductive trade‐offs in different animal taxa, particularly in birds. Most bird studies have focused on the costs of chick rearing in altricial species. These costs have been assumed to be low in precocial species, but this aspect has been little studied. We used long‐term individual reproductive data from the common goldeneye Bucephala clangula, an iteroparous precocial duck with uniparental female care, to examine whether brood rearing carries costs that affect future reproductive performance. All females were experienced breeders, and possible differences in female quality were ruled out. We compared within‐individual (between‐year) changes in clutch size, hatching date and body mass between females that had reared a brood in the previous year and females that had not. It turned out that brood rearing involved a cost in terms of clutch size and hatching date the next year, but not in terms of body mass: females that had reared a brood in the previous year laid relatively smaller clutches and laid relatively later than females that had not reared a brood. Our results show that normal brood rearing in a precocial species involves costs that affect future reproduction.

FACTORS INFLUENCING INCUBATION EGG-MASS LOSS FOR THREE SPECIES OF WATERFOWL

Abstract Many bird eggs lose ∼15% of their fresh mass before pipping, but individual species have been reported to lose 10–23%. Most published estimates have been imprecise due to small sample sizes. Moreover, published estimates of within- or among-species variance components of mass loss are virtually unknown. We modeled the influence of nest type, clutch size, and egg size on daily mass loss of Mallard (Anas platyrhynchos), Common Goldeneye (Bucephala clangula), and Hooded Merganser (Lophodytes cucullatus) eggs and compared fractional mass loss among species. Mallard eggs in artificial nest cylinders lost more mass than those in ground nests, but were unaffected by nest initiation date. Average-sized eggs in Mallard ground nests, Mallard cylinder nests, and Common Goldeneye and Hooded Merganser nest boxes lost 7.9 g (15.2%), 10.8 g (20.3%), 10.3 g (15.5%), and 9.2 g (15.8%) of fresh mass, respectively. For all species, daily mass loss increased as incubation progressed and was affected by an interactio...

Reproductive performance of Common Goldeneye Bucephala clangula females in relation to age and lifespan

We studied the effects of female age and length of lifespan on reproductive performance in the Common Goldeneye Bucephala clangula, a precocial species with self‐feeding chicks. Dependent variables studied were the occurrence of failed nesting attempts and non‐breeding years, clutch size, nesting and hatching success, female condition and recovery rate of offspring. To avoid misinterpretations resulting from age‐dependent quality changes in the cohorts, individuals with different lifespans were separated in the analyses. There was no evidence that females of different lifespan differed in reproductive strategy. The data revealed no significant differences in nest losses, occurrence of non‐breeding years, timing of nesting or clutch size, but the physiological condition of short‐lived females was poorer than that of longer living females. This accords with the prediction that poor‐quality females invest proportionally more in reproduction than high‐quality females and consequently die earlier. The most productive individuals were those that lived longest. The only indication of senescence was the low recovery rate of offspring produced by old females. The last breeding attempt did not differ in any observable respect from the penultimate attempt, implying that the last investment in reproduction was no heavier than the previous one.

Nest‐site limitation and density dependence of reproductive output in the common goldeneyeBucephala clangula: implications for the management of cavity‐nesting birds

Summary Hole‐nesting birds are frequently faced with a shortage of suitable nest sites in regions of intensive forest management. Nest boxes are sometimes provided to alleviate nest‐site limitation in cavity‐nesting waterfowl and are also recommended for several rare and endangered species. However, the impacts on effective breeding numbers and breeding success have rarely been considered, particularly in instances where density dependence might operate. We experimentally manipulated nest sites to assess limits on the population size of a secondary cavity‐nesting species, the common goldeneyeBucephala clangula, living on freshwater lakes. We also examined density dependence in their reproductive output. Breeding pairs were counted in experimental and control areas over a 12‐year period; for 4 years (1988–91) before nest box addition (1992–94 in the experimental area) and for 5 years (1995–99) afterwards. Broods were counted each year between 1988 and 1999 to study reproductive output. Mean number of pairs per lake increased after the addition of nest boxes in the experimental area but not in the control area. However, neither the mean number of broods per lake nor the mean number of fledged birds per lake increased significantly in the experimental area. When the whole period of 1988–99 was considered and data pooled from all the lakes, the numbers of broods and fledged birds showed negative density dependence of reproductive output. Our results indicate that nest sites limit the population size of breeding common goldeneye, but show also that density‐dependent factors operate to limit reproductive output. The possibility that density dependence may negate management actions directed at increasing breeding numbers in cavity‐nesting waterfowl should be considered carefully before taking these actions. This also applies to nest box provisioning programmes aiming to manage populations of endangered species.

Hunting disturbance on a large shallow lake: the effectiveness of waterfowl refuges

Disturbance is most likely to have an impact during those periods of the annual cycle when food is scarce and birds have difficulty in meeting their energy requirements. The provision of disturbance‐free refuges has been shown to enhance the abundance and diversity of waterfowl wintering on such sites. Lough Neagh, a large shallow lake in Northern Ireland, hosts internationally important numbers of wintering waterfowl, the most numerous being Common Pochard Aythya ferina, Tufted Duck A. fuligula, Greater Scaup A. marila and Common Goldeneye Bucephala clangula. Hunting is the predominant winter recreational activity. A small number of refuges have been provided to limit the effects of shooting disturbance on the wintering populations. The use of one of these refuges (Doss Bay) was studied during the winter of 1997/8 and compared with a non‐refuge site (Brockish Bay) during the winter of 1998/9. Shooting intensity was greater at weekends than midweek, and significantly more birds used the refuge at weekends than midweek during the shooting season. In contrast, significantly fewer birds were observed in Brockish Bay at weekends. This trend ceased when the shooting season closed, suggesting that the effect was due to shooting disturbance. Furthermore, significantly fewer birds used Doss Bay after the shooting season had closed, whereas significantly more birds were observed at Brockish Bay. Shooting disturbance had the greatest impact on dabbling duck species and rails at both sites. Diving ducks moved away from shoreline disturbance to shallow areas where they could still feed. The value of shoreline refuges for waterfowl populations on lakes is discussed.

Costs and benefits of female-biased natal philopatry in the common goldeneye

Sex-biased natal dispersal in long-lived species may result in interactions between parents and mature young of the philopatric sex. To investigate the evolutionary basis of natal philopatry in a noncooperative species, the common goldeneye Bucephala clangula, we studied possible costs and benefits of simultaneous breeding of females and philopatric daughters. We did not find any fitness consequences of a daughter's breeding on their mother's breeding in terms of nest-site selection, body weight, clutch size, hatching date, or hatching success. Our results, therefore, did not support the assumption of the local resource competition hypothesis, that the natally philopatric sex should be more costly to a breeding parent. As possible benefits for daughters returning to their natal area, we tested inheritance of nest sites from mothers and explored whether daughters utilize the presence of their mother by parasitically sneaking into her mother's nest. Daughters' nest-site selection was not associated with the presence of their mothers. A comparison between daughters and control females revealed that daughters chose their nest site closer to their natal nest than expected by nest-site availability alone. Daughters could not expect to inherit a nest site from their mother, and we did not find other indications of cooperation between relatives either. The mother's clutch size did not increase in the year breeding with the daughter, indicating daughters do not parasitize their mother's nest. We suggest that benefits such as decreased nest predation risk associated with nesting close to the natal nest site may be important in the natal philopatric behavior of the species.

Migration patterns and sex ratios of diving ducks wintering in Northern Ireland with specific reference to Lough Neagh

Several duck species exhibit differential migration, whereby females settle further south than males on the winter grounds after the autumn migration. This is most exaggerated in the diving ducks. In Northern Ireland generally, the migration patterns of Common Pochard Aythya ferina, Tufted Duck A. fuligula, Greater Scaup A. marila, and Common Goldeneye Bucephala clangula are similar to those observed in Great Britain. On Lough Neagh in particular, the sex ratios of wintering flocks of diving ducks were observed between the winters of 1996 and 1999. On average, 79% of Common Pochard, 72% of Tuf ted Duck and 66% of Common Goldeneye wintering on Lough Neagh were male. The possible reasons for differential migration of the sexes include body size dimorphism resulting in different cold temperature tolerances, advantages for males in returning to breeding grounds sooner and intersexual competition excluding the less competitive females to areas further south.

Identification of parasitized nests by using egg morphology in the Common Goldeneye: an alternative to blood sampling

We used data from three Common Goldeneye Bucephala clangula populations in Finland to study if the variation between females in egg morphology, as measured using a method developed by Eadie (1989), can be used to identify parasitized clutches. Eadie's method is based on z‐score standardized measures of length, width, and weight of eggs. Using these measures, Euclidean distance for each pair of eggs within a clutch was calculated. Euclidean distance between the two most dissimilar eggs (maximum Euclidean distance, MED) was used as the criterion to identify parasitized clutches. Test clutches of 3 eggs that included one egg from each of three different females had a higher MED (2.80) than 3‐egg clutches that included eggs from one female only (2.05), proving that there is statistically significant variation in egg morphology between females. Test clutches that included three eggs from each of three different females (9 eggs in all) had a mean MED of 4.51. The mean MED of naturally parasitized clutches (4.83) was higher than that of nonparasitized clutches (2.12). Further analyses suggested that MED>3.0 can be used as a conservative and reliable criterion to identify parasitized clutches. Our results confirm that Eadie's method is reliable enough to identify parasitized clutches in Common Goldeneyes.

Nest-Site Selection in Relation to Habitat Edge: Experiments in the Common Goldeneye

Habitat edges affect several ecological phenomena, usually known as the edge-effect concept. One of its basic principles is the ecological trap hypothesis which assumes that birds are attracted to nest near habitat edges where food supplies may be greater but nest predation is higher. We studied nest-site selection in relation to the lake shore/forest habitat edge in the Common Goldeneye Bucephala clangula, a hole-nesting duck, using two types of experiment. First, we examined nest-site prospecting by erecting nest boxes with traps at the shoreline and inside the forest at varying distances from the shoreline. Secondly, we examined nest-site selection in three study areas by erecting nest boxes in pairs: at the shoreline and at varying distances inside the forest. In addition we experimentally measured nest predation rate in shore and forest boxes using artificial nests. Goldeneye females prospected shore and forest boxes equally. However, the final decision was in favour of shore boxes: within a box pair, the shore box was occupied first in all three study areas. There was no difference in nest predation rate between shore and forest boxes, except in one study area where predation rate was lower, not higher, in shore boxes. Thus, while Goldeneye females clearly exhibit a pattern of nest-site selection in relation to habitat edge, the ecological trap hypothesis is not supported so far as the risk of predation is considered. Increased predation risk associated with the period of getting hatched young out of the nest to a brood-rearing lake may be the reason for the rejection of forest boxes.

Factors affecting clutch Size and Duckling Survival in the Common Goldeneye Bucephala clangula

Female age and condition as well as nesting schedule may affect clutch size and chick survival, which both are important factors affecting the annual reproductive output. Clutch size and chick survival are often interrelated in altricial birds but in precocial species the interrelation is dubious. To study factors affecting clutch size and the survival of ducklings in the common goldeneye Bucephala clangula, we examined ringing‐recovery data, supplied by ringers, from seven intensively studied goldeneye populations from different parts of Finland. Due to large sample sizes it was possible to distinquish the effects of interrelated variables, e.g. female age and hatching date. Clutch size was significantly associated with both female age and hatching date; first‐time breeders and late breeders had small clutches. Clutch size was not associated with female condition. The recovery rate of ducklings was associated with hatching date (low in late broods) but not with female age, condition or brood size. The natal brood sizes of recruited female ducklings did not differ from annual averages, but the natal hatching date of recruited females was earlier and their mothers were older than annual averages in the populations into which the recruited females were bom. The timing of nesting was the most important factor affecting the reproductive output of common goldeneye females in a given year.

Natal Philopatry and the Local Resource Competition Hypothesis: Data from the Common Goldeneye

Sex-biased local resource competition (LRC) between parents and offspring has been suggested to exert selection pressure on progeny sex ratio variation in birds. In a recent article Weatherhead and Montgomerie (1995) questioned that the assumptions underlying the LRC hypothesis are applicable to birds. We here study the basic assumptions of the LRC hypothesis with data from the Common Goldeneye Bucephala clangula. First, we found strong female-biased natal philopatry, as expected in Anseriformes. Second, of all the females breeding in the study area, individuals born there comprised a major proportion each year. Third, we document a considerable overlap between home ranges of breeding mothers and daughters. Our results, combined with results from other Common Goldeneye populations and other Bucephala species, give strong support for the assumptions of the LRC hypothesis to be applicable to birds, at least to some species.

Monitoring nest box use by cavity‐nesting ducks on acid‐stressed lakes in Ontario, Canada

Nest boxes erected on 75 small lakes near Sudbury, Canada were monitored annually between 1987 and 1996 to measure the response of cavity‐nesting waterfowl to changing chemical and biological conditions of their nesting habitat from the effects of acidification. Nest boxes were used mainly by common goldeneyes Bucephala clangula and hooded mergansers Lophodytes cucullatus, although a few were occupied by common mergansers Mergus merganser and wood ducks Aix sponsa. Use by hooded mergansers and wood ducks increased from 1987 to 1996, while use by goldeneyes remained stable. Patterns in nest box use reflected general population trends observed in the area. Interspecific nest parasitism also increased to 33% of all nests in 1996, probably a consequence of more hooded merganser nests. Clutch size, nesting and hatching success of goldeneye and hooded merganser eggs were similar to values reported for conspecifics in other studies. Overall, interspecific nest parasitism did not appear to affect the nesting success of either species. Although goldeneyes nested more often on fishless lakes early in the study, overall, fish presence, pH‐value, lake area and connectivity were not related to nesting attempts or measures of nesting success for either species. Therefore, it is believed that for common goldeneyes and hooded mergansers currently breeding in the acid‐stressed Sudbury area, habitat characteristics have little influence on nest site selection, particularly when compared to their documented effects on brood‐rearing. However, monitoring of nest boxes may prove a less expensive method than aerial surveys to track population responses of cavity‐nesting species to chemical improvements.

Common goldeneyes adjust maternal effort in relation to prior brood success and not current brood size

Parental investment theory predicts that parental effort should be related to the reproductive value of the current brood. This depends on both the number of young and the survival prospects of each of them. Thus parents may provide more care to larger broods either because of (1) the direct effect of brood size per se on reproductive value (the “brood size” hypothesis) or because (2) past mortality, reflected in current brood size, predicts future mortality of the brood and hence its reproductive value (the “brood success” hypothesis). Earlier studies have not attempted to distinguish between these alternatives. We tested the hypotheses in the precocial, nidifugous common goldeneye Bucephala clangula, a species with uniparental female care. Maternal effort was measured as the time spent by the female in rearing the brood. We found that brood size itself is not associated with maternal effort, but that females modify their maternal effort according to the mortality already experienced by the brood, supporting the prediction of the brood success hypothesis. We also found that brood mortality varied considerably between broods and that previous mortality predicts future mortality within broods, basic assumptions of the brood success hypothesis.

Runting of Ducklings Associated with Cochlosoma anatis Infection

Ducklings, especially common goldeneye (Bucephala clangula), experiencing poor weight gain and delayed development were reported from a waterfowl park during June and July of 1990. Runting was first noticed between days 5 and 10 post-hatch in the "brooder" building, and although ducklings appeared active and were feeding, they developed at a slower rate than other members of their clutch. Many ultimately died of emaciation and gram-negative bacterial septicemia. Necropsies of affected ducklings revealed large numbers of the intestinal flagellate Cochlosoma anatis, in both the small and the large intestine; however, autolysis impaired histological interpretation in many cases. Inoculation of 1-day-old Muscovy ducklings with feces containing large numbers of C. anatis resulted in poor weight gain and delayed tail-feather development compared with uninoculated control ducklings. Weight gain improved after treatment with metronidazole. Cochlosoma anatis is associated with the runting syndrome observed in ducklings at the waterfowl park.

The diet of insectivorous ducklings and the acidification of small Ontario lakes

We examined the diet of insectivorous ducklings of four species of waterfowl, Common Goldeneye (Bucephala clangula), Ring-necked Duck (Aythya collaris), Hooded Merganser (Lophodytes cucullatus), and American Black Duck (Anas rubripes), collected from small lakes covering a range of acidity in northeastern Ontario. The numbers of Odonata larvae, aquatic Hemiptera, aquatic Coleoptera, and Trichoptera larvae eaten by the ducklings were estimated from combined esophageal and gizzard contents and analysed with respect to differences in lake acidity and fish presence. Ducklings of all species, especially Common Goldeneye and Hooded Merganser, ate significantly more nektonic prey, especially Notonectidae (Hemiptera) and Dytiscidae (Coleoptera), from lakes without fish than from lakes with fish. Ducklings of species other than American Black Duck ate more Anisoptera larvae on acidic lakes. American Black Duck ducklings ate more teneral Odonata on acidic lakes. There was a tendency for more Trichoptera larvae to be eaten on non-acidic lakes than on acidic lakes. All four species adjusted, to some extent, for the absence of acid-sensitive prey in acidified lakes by feeding on prey that are most abundant under acidic, Ashless conditions. Differences in diet among species were related to differences in diving and foraging behaviour, and to hatch date.

Movements and survival of Common Goldeneye broods near Sudbury, Ontario, Canada

We examined movements and survival of Common Goldeneye (Bucephala clangula) broods in a highly acidified area on the Canadian Precambrian Shield near Sudbury, Ontario, during 1989 and 1990. When data from the 2 years were combined, a total of 16 females had led their broods from nesting to rearing lakes, while only 4 had raised their broods on the nesting lake. Initial brood-rearing lakes contained a greater biomass of invertebrate prey and were closer to neighbouring lakes than corresponding nesting lakes. Eight broods undertook 17 secondary movements between rearing lakes. These movements were not related to differences between lakes in prey biomass or distance to neighbouring lakes. Daily survival rates of age-class I and age-class II ducklings did not differ between years. When data from the 2 years were combined, it was found that duckling survival was not related to brood movements or prey biomass. Duckling survival was higher on clustered lakes than on isolated lakes. The availability of alternate brood-rearing lakes with sufficient invertebrate prey, in addition to the primary brood-rearing lake, may be an important factor influencing Common Goldeneye brood movements and survival in our study area.