Ecological segregation among Thick-billed Murres (Uria lomvia) and Common Murres (Uria aalge) in the Northwest Atlantic persists through the nonbreeding season

To study the influence of inter- and intra-specific interactions on patterns of ecological segregation in nonbreeding habitat, we used geolocators to track year-round movements of congeneric and partially sympatric Thick-billed Murres (Uria lomvia (L., 1758)) and Common Murres (Uria aalge (Pontoppidan, 1763)) from seven Canadian colonies during 2007–2011. Locations from 142 individuals were (i) examined for species- and colony-specific spatiotemporal patterns, (ii) mapped with environmental data, and (iii) used to delineate core wintering areas. Compared with Common Murres, Thick-billed Murres dispersed across a wider range of latitudes and environments, had larger winter ranges, and showed greater variation in seasonal timing of movements. These interspecific differences were consistent at two scales: among colonies spanning a wide latitudinal range and at a sympatric colony. Intraspecifically, nonbreeding ecological segregation was more pronounced among colonies of Thick-billed Murres than of Common Murres: colonies of Thick-billed Murres tended to follow distinct movement patterns and segregate by latitude, whereas colonies of Common Murres segregated very little; moreover, the extent of segregation was more variable among Thick-billed Murres than Common Murres. For Thick-billed Murres, rather than complete divergence of winter ecological niche from Common Murres, we found a “widening” of an overlapping niche. This strategy of increased movement flexibility may enable Thick-billed Murres to mitigate competition both intra- and inter-specifically; we propose this movement strategy may have played a role in species divergence.

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Ecological relationships between Common Murres, Uria aalge, and Thick-billed Murres, Uria lomvia, at the Gannet Islands, Labrador. III. Feeding ecology of the young

Canadian Journal of Zoology ◽

10.1139/z87-253 ◽

1987 ◽

Vol 65 (7) ◽

pp. 1638-1649 ◽

Cited By ~ 32

Author(s):

T. R. Birkhead ◽

D. N. Nettleship

Keyword(s):

Caloric Intake ◽

Interspecific Difference ◽

Uria Aalge ◽

Uria Lomvia ◽

Ice Breakup ◽

Common Murre ◽

Interspecific Differences ◽

Daubed Shanny ◽

Common Murres ◽

Capelin Mallotus Villosus

A simultaneous comparison of the foods of Common Murre, Uria aalge, and Thick-billed Murre, Uria lomvia, chicks at the same location showed that the species composition of fish fed to chicks of the two murre species differed significantly. In both years of the study, Common Murre chicks were fed predominantly capelin, Mallotus villosus (78–80% by weight), whereas Thick-billed Murre chicks were fed mainly daubed shanny, Lumpenus maculatus (61–70% by weight). Thick-billed Murres tended to feed their chicks more frequently than Common Murres, probably because in both years the mean caloric value of their prey was lower than that of the Common Murre's. No other statistically significant interspecific differences were consistent between years. Prey lengths and weights overlapped considerably between the murre species, and the caloric intake of chicks showed no consistent interspecific difference. Marked interyear differences in feeding rate, prey size, and caloric intake occurred in both species. In 1982 ice breakup was late, and the murres' breeding seasons were delayed; this appeared to result in poor synchronization between the temporal pattern of food availability and the timing of each species' chick-rearing period, and the caloric intakes of chicks of both species were lower in that year than in 1983.

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Ecological relationships between Common Murres, Uria aalge, and Thick-billed Murres, Uria lomvia, at the Gannet Islands, Labrador. I. Morphometrics and timing of breeding

Canadian Journal of Zoology ◽

10.1139/z87-251 ◽

1987 ◽

Vol 65 (7) ◽

pp. 1621-1629 ◽

Cited By ~ 34

Author(s):

T. R. Birkhead ◽

D. N. Nettleship

Keyword(s):

Egg Laying ◽

Laying Date ◽

Uria Aalge ◽

Uria Lomvia ◽

Ecological Relationships ◽

Ice Breakup ◽

Common Murre ◽

Common Murres ◽

Adult Body Weight ◽

One Year

Several aspects of the breeding biology of Common Murres (Uria aalge) and Thick-billed Murres (Uria lomvia) in 1981–1983, at the Gannet Islands, Labrador, are described. At this colony there were ca. 60 000 pairs of Common Murres, and 1400 pairs of Thick-billed Murres. Common Murres were slightly heavier and had significantly shorter wings, and longer, narrower bills than Thick-billed Murres. The timing of egg laying varied between years (late breeding in one year was associated with late ice breakup), but the median laying date of Common Murres was consistently earlier (by up to 10 days) than that of Thick-billed Murres. For both species median laying dates fell between mid and late June each year. Common Murre eggs were larger and relatively longer than Thick-billed Murre eggs, but in both species fresh egg weight was about 11% of adult body weight. Incubation periods were similar in each species (33 days), but chick-rearing periods were longer in Common Murres (24 days) than in Thick-billed Murres (21 days) in all years. Seasonal patterns of colony attendance were broadly similar in the two species each year, except that Common Murres showed a consistent increase in numbers between laying and chick departure, and tended to remain at the colony for less time after chicks had departed compared with Thick-billed Murres. All birds of both species left the colony by mid-September each year.

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Thickness of Common Murre (Uria aalge) eggshells in Atlantic Canada

The Canadian Field-Naturalist ◽

10.22621/cfn.v128i1.1553 ◽

2014 ◽

Vol 128 (1) ◽

pp. 72 ◽

Cited By ~ 2

Author(s):

Donald W. Pirie-Hay ◽

Alexander L. Bond

Keyword(s):

Newfoundland And Labrador ◽

Shell Thickness ◽

Egg Size ◽

Environmental Pollutants ◽

Maternal Investment ◽

Uria Aalge ◽

Uria Lomvia ◽

Common Murre ◽

Common Murres ◽

Nesting Material

Reported values for eggshell thickness in Common Murre (Uria aalge) are few, and even fewer since the decline in use of organochlorine pesticides and other environmental pollutants that caused significant thinning of shells. The eggshells of Common Murres and Thick-billed Murres (Uria lomvia) are among the thickest and heaviest, proportionately, of any bird and this represents a non-trivial maternal investment. We measured the length and breadth of Common Murre eggs collected from Machias Seal Island, New Brunswick, in 2006, and Gull Island, Newfoundland and Labrador, in 2012, and we measured the thickness of the eggshells. Shell thickness was not related to egg size or volume, and it varied in individual eggs. The shells of Common Murre eggs from Machias Seal Island (mean and standard deviation [SD] (0.767, SD 0.078 mm) and Gull Island (0.753, SD 0.057 mm) were significantly thicker than any previously reported value and among the thickest of all birds. Such thickness is likely a result of nesting on rock substrate with no nesting material and, perhaps, high breeding densities.

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Ecological relationships between Common Murres, Uria aalge, and Thick-billed Murres, Uria lomvia, at the Gannet Islands, Labrador. II. Breeding success and site characteristics

Canadian Journal of Zoology ◽

10.1139/z87-252 ◽

1987 ◽

Vol 65 (7) ◽

pp. 1630-1637 ◽

Cited By ~ 32

Author(s):

T. R. Birkhead ◽

D. N. Nettleship

Keyword(s):

Breeding Success ◽

Breeding Site ◽

Uria Aalge ◽

Uria Lomvia ◽

Short Supply ◽

Breeding Sites ◽

Ecological Relationships ◽

Site Characteristics ◽

Common Murres ◽

Flat Ground

At the Gannet Islands, Labrador, the proportion of Thick-billed Murres (Uria lomvia) that successfully reared a chick that left the colony was significantly lower (mean = 63%) than that of Common Murres (Uria aalge; 82%) in each of 3 years of study. The physical and social features of the breeding site were the only factors known to influence breeding success. For both murre species, breeding success increased with ledge width, and whereas most Common Murres bred on the widest ledges, relatively few Thick-billed Murres did so. The success of each species did not differ significantly on ledges of the same width. We suggest that Common and Thick-billed murres competed for breeding sites and that Common Murres obtained a disproportionate share of the "best" sites. This occurred because Common Murres outnumbered Thick-billed Murres by about 40:1 and because cliff habitat was in short supply. Whereas Thick-billed Murres bred only on cliffs, Common Murres were able to breed on cliffs and flat ground nearer sea level. Additional circumstantial evidence supports the idea that Common and Thick-billed murres at the Gannet Islands compete for breeding sites.

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Ecological interactions and habitat modification in nesting Common Murres, Uria aalge

Bird Conservation International ◽

10.1017/s0959270900003154 ◽

1996 ◽

Vol 6 (3) ◽

pp. 261-269 ◽

Cited By ~ 8

Author(s):

Julia K. Parrish ◽

Robert T. Paine

Keyword(s):

Reproductive Output ◽

Habitat Modification ◽

Haliaeetus Leucocephalus ◽

Uria Aalge ◽

Ecological Interactions ◽

Bald Eagles ◽

Predator Removal ◽

Common Murre ◽

Corvus Caurinus ◽

Common Murres

SummarySeabird populations suffer from a variety of natural and human-induced sources of mortality and loss of lifetime reproductive output. On the outer coast of Washington State, Common Murre Uria aalge populations have been in decline for approximately the last decade and are currently reproductively active only at Tatoosh Island. These murres nest in two basic habitat types: crevices (25% of the population) and larger cliff-top subcolonies (75%). Murres in cliff-top subcolonies have suffered dramatic reductions in reproductive success in recent years relative to conspecifics nesting in the crevices, primarily due to egg predation by Glaucous-winged Gulls Larus glaucescens and Northwestern Crows Corvus caurinus, facilitated by the presence of Bald Eagles Haliaeetus leucocephalus. Because predator removal is not feasible and creation of additional crevice habitat is difficult, expensive and potentially ineffective, we have designed a temporary habitat modification (the “silk forest”) which replaces the natural vegetation cover and modifies the interaction between murres and eagles. Within the test subcolony, murres nesting under and immediately adjacent to the silk forest produced nearly twice as many eggs per square metre as their conspecifics nesting in adjacent exposed-ground areas.

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Exceptional variation in the appearance of Common Murre eggs reveals their potential as identity signals

The Auk ◽

10.1093/ornithology/ukab049 ◽

2021 ◽

Author(s):

Tim R Birkhead ◽

Jamie E Thompson ◽

Amelia R Cox ◽

Robert D Montgomerie

Keyword(s):

Uria Aalge ◽

Quantitative Evidence ◽

Breeding Group ◽

Common Murre ◽

Trimodal Distribution ◽

Common Murres ◽

Egg Traits ◽

Breeding Groups ◽

Different Parts

Abstract We studied the ground colors and maculations of 161 Common Murre (Uria aalge) eggs laid by 43 females in 3 small breeding groups on the cliffs of Skomer Island, Wales, in 2016–2018. Both the colors and maculations varied much more among than within females, providing quantitative evidence for the egg traits that might facilitate the parents’ ability to identify their own eggs on the crowded breeding ledges where the density is typically ~20 eggs m–2. Ground colors had a trimodal distribution of hue values (whitish to pale brown, pale blue, or vivid blue-green) and maculations ranged from none to complex squiggles and blotches. The eggs laid by each female in different years were similar to one another, and replacement eggs laid by females within years were also more similar to their first egg than to other eggs in the same breeding group. Egg appearance did not differ among the 3 breeding groups that we studied. Our findings thus support anecdotal observations that, within and between years, female Common Murres lay eggs that have similar ground colors and maculations. We do not, however, find evidence that there is much difference among the eggs laid in different parts of a colony.

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Mild segregation in the breeding preferences of an invasive anuran (Discoglossus pictus) and its main native competitor (Epidalea calamita) in ephemeral ponds

Amphibia-Reptilia ◽

10.1163/15685381-20191149 ◽

2019 ◽

Vol 40 (4) ◽

pp. 425-435 ◽

Cited By ~ 2

Author(s):

Eudald Pujol-Buxó ◽

Gabriel M. Riaño ◽

Gustavo A. Llorente

Keyword(s):

Alien Species ◽

Native Species ◽

Evolutionary History ◽

Reproductive Season ◽

Breeding Sites ◽

Ecological Segregation ◽

Ephemeral Ponds ◽

Interspecific Differences ◽

Discoglossus Pictus ◽

Epidalea Calamita

Abstract The choice of breeding sites by pond-breeding anurans has notable consequences for the fitness of larvae. Hence, beyond pond typology and phenology, adults can also discriminate according to several other features, for instance to favour allotopy with potential competitors. However, the lack of shared evolutionary history might impede proper ecological differentiation with alien species during the first stages of invasions. Here, we studied several possible sources of ecological segregation between the invasive Discoglossus pictus and the native Epidalea calamita in ephemeral ponds, where the native toad hardly had competition before the arrival of the invasive frog. During spring of 2016, we periodically surveyed 69 ephemeral ponds in three areas with different invasion histories to detect the presence/absence of eggs and tadpoles of these species. Invasive D. pictus started breeding earlier than E. calamita, but differences were not significant. Similarly, there were not clear differences among areas with different invasion histories. However, we found for both species a mutual tendency to directly avoid larval syntopy at the end of the reproductive season. We also found interspecific differences in the features that both species use for pond choice, preferring the native species shallower and less vegetated ephemeral ponds. Globally however, co-occurrence was high, pointing at other processes as key to the coexistence between both species in these habitats.

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