Northernmost Colony Research Articles

The role of Magellanic penguins (Spheniscus magellanicus) on landscape dynamics and lithic taphonomy in La Pastosa Islet, North Patagonia, Argentina

This study presents the results of a systematic survey of La Pastosa Islet, located 700 m off the west coast of Río Negro, Argentina. This small islet has the particularity of hosting the northernmost colony of Magellanic penguins ( Spheniscus magellanicus) to date and contains evidence of its use by hunter-gatherer groups during the late Holocene. This growing colony started around 2002 and has had a significant impact on the subsurface archeological record of the islet by increasing erosion and exposing buried materials through nest excavation, particularly lithic artifacts. The spatial analysis of the distribution of artifact and penguin burrows indicates that the actions of the latter generated a “snapshot” of the subsurface distribution of the lithic record. The observed distribution suggested higher discard rates at the center of the islet. Furthermore, this study shows the synergy between both types of records in the formation dynamics of the lithic landscape and the agency of penguins as active landscape engineers. Finally, the obtained results have important implications for the management of the protected sector of the recently established Islote Lobos National Park, within which the study area is located.

Multi‐colony tracking of two pelagic seabirds with contrasting flight capability illustrates how windscapes shape migratory movements at an ocean‐basin scale

Migration is a common trait among many animals allowing the exploitation of spatiotemporally variable resources. It often implies high energetic costs to cover large distances, for example between breeding and wintering grounds. For flying or swimming animals, the adequate use of winds and currents can help reduce the associated energetic costs. Migratory seabirds are good models because they dwell in habitats characterized by strong winds while undertaking very long migrations. We tested the hypothesis that seabirds migrate through areas with favourable winds. To that end, we used the SEATRACK dataset, a multi‐colony geolocator tracking dataset, for two North Atlantic seabirds with contrasting flight capabilities, the black‐legged kittiwake Rissa tridactyla and the Atlantic puffin Fratercula arctica, and wind data from the ERA5 climate reanalysis model. Both species had on average positive wind support during migration. Their main migratory routes were similar and followed seasonally prevailing winds. The general migratory movement had a loop‐shape at the scale of the North Atlantic, with an autumn route (southward) along the east coast of Greenland, and a spring route (northward) closer to the British Isles. While migrating, both species had higher wind support in spring than in autumn. Kittiwakes migrated farther and benefited from higher wind support than puffins on average. The variation in wind conditions encountered while migrating was linked to the geographical location of the colonies. Generally, northernmost colonies had a better wind support in autumn while the southernmost colonies had a better wind support in spring, with some exceptions. Our study helps understanding how the physical environment shapes animal migration, which is crucial to further predict how migrants will be impacted by ongoing environmental changes.

Low Population Structure and Genetic Diversity in Rhinolophus blasii at the Northern Limit of Its European Range: Are there Undiscovered Colonies?

The Blasius's horseshoe bat (Rhinolophus blasii) shows a fragmented distribution in the European part of its range, and its populations are threatened by many human-induced factors. The status and distribution of the species in Romania are largely unknown. In recent years, regular bat surveys and monitoring have confirmed the presence of the species in north-western Romania, in Gălăşeni Cave, Pădurea Craiului Mountains, representing the northernmost distribution point of R. blasii in Europe. In our study we investigated whether this northernmost colony is genetically isolated from, or related to, larger populations in south-western Romania. A combined analysis of two mitochondrial (12S, HVII) and two nuclear (RAG2, DBY7) genetic markers was used in order to reveal possible relationships between these populations. The small number of haplotypes, the presence of shared haplotypes and overall low population structure suggest that the south-western and north-western Romanian populations are related through yet unidentified colonies of R. blasii, with continuous migration between them. Our results also indicate that the R. blasii colony from Gălăşeni Cave was established by female individuals migrating not far from their birthplace. To preserve this marginal population in a long term, conservation measures need to be strengthened and properly enforced, in parallel with the search for new R. blasii colonies in the region. To our knowledge, the present work represents the only molecular study of R. blasii in Europe.

Spatial and temporal diet variability of Ad\xe9lie (Pygoscelis adeliae) and Emperor (Aptenodytes forsteri) Penguin: a multi tissue stable isotope analysis

The Ross Sea, Antarctica, supports large populations of Emperor Penguin (Aptenodytes forsteri) and Adélie Penguin (Pygoscelis adeliae), two key meso-predators that occupy high trophic levels. Despite these species are largely studied, little is known about their diet outside the breeding period. In the present study, we investigated the intra-annual diet of Adélie and Emperor Penguins belonging to five colonies in the Ross Sea through the stable isotope analysis of different tissues (feathers and shell membranes), synthetized in different seasons, and guano that indicates recent diet. Penguin samples and prey (krill and fish) were collected during the Antarctic spring–summer. δ13C and δ15N of tissues and guano indicate spatio-temporal variation in the penguin diet. The krill consumption by Adélie Penguins was lowest in winter except in the northernmost colony, where it was always very high. It peaked in spring and remained prevalent in summer. The greatest krill contribution to Emperor Penguin’s diet occurred in summer. The relative krill and fish consumption by both species changed in relation to the prey availability, which is influenced by seasonal sea ice dynamics, and according to the penguin life cycle phases. The results highlight a strong trophic plasticity in the Adélie Penguin, whose dietary variability has been already recognized, and in the Emperor Penguin, which had not previously reported. Our findings can help understand how these species might react to resource variation due to climate change or anthropogenic overexploitation. Furthermore, data provides useful basis for future comparisons in the Ross Sea MPA and for planning conservation actions.

Diet composition of expanding breeding populations of the Magellanic Penguin

ABSTRACTThe Magellanic Penguin (Spheniscus magellanicus) is the most abundant and widely distributed seabird breeding on the Patagonian Coast of Argentina. We combined conventional stomach content and stable isotope analysis to assess Magellanic Penguin diet during the chick rearing stage at the two northernmost colonies in an area subject to fisheries. In 2011 and 2013, Thornfish (Bovichtus argentinus) was the main prey by mass at Complejo Islote Lobos (63.0% and 32.3%, respectively) and Argentine Anchovy (Engraulis anchoita) at Estancia San Lorenzo (85.2 and 63.3%, respectively). Magellanic Penguins from both colonies showed low isotopic niche overlap in 2011 (36%) and no overlap in 2013, suggesting a different use of prey species and/or foraging areas. Stable isotope mixing models showed that Argentine Anchovy (52.8%) and Thornfish (65.9%) were the main prey at Complejo Islote Lobos in 2011 and 2013, respectively, while Patagonian Redfish (Sebastes oculatus) (46.4%) and Squat Lobster (Munida gregaria) (50%) were the main prey at Estancia San Lorenzo in 2011 and 2013, respectively. Results show that in addition to Argentine Anchovy, previously recognized as main prey for breeding Magellanic Penguins in northern Patagonia, other juvenile or small sized fish are important diet items. Diet results suggest different scenarios of food conditions for each colony, despite the relative short distance between breeding locations. The low contribution of Argentine Hake (Merluccius hubbsi) and Argentine Shortfin Squid (Illex argentinus) suggests a low trophic overlap with commercial fisheries. The information provided is key to understand changes in the marine ecosystem and potential penguin-fishery interactions.

The effect of long-range transport, trophic position and diet specialization on legacy contaminant occurrence in great skuas, Stercorarius skua, breeding across the Northeast Atlantic

High levels of halogenated organic contaminants (HOCs) have been found in the marine predatory seabird great skua (Stercorarius skua) from breeding colonies in the Northeastern Atlantic, with large unexplained inter-colony variation. The present study aimed at analyzing if the HOCs occurrence in breeding great skuas in remote colonies was explained by local baseline food web exposure determined by long-range transport, or by ecological factors such as diet specialization and relative trophic position in the breeding area. The occurrence of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) was analyzed in plasma of 204 adult great skuas collected over two years (2008 and 2009) and 5 colonies across the North-Atlantic from Shetland to Svalbard. The ΣHOCs levels in plasma ranged across two orders of magnitude, from 40 to 7600 ng/g (wet weight) and differed significantly across the great skua colonies. The variation in contaminant occurrence among colonies did not reflect long-range transport through a latitudinal or remoteness gradient, as the second northernmost colony (Bjørnøya), had the highest contaminant concentrations. No latitudinal or remoteness gradient was evident in the contaminant pattern among the colonies. The contaminant levels increased significantly with increasing δ15N values, and regurgitated pellets of undigested prey suggested that great skuas with higher δ15N values had a higher proportion of bird prey in their diet, mostly seabirds. In contrast, great skuas from colonies with lower δ15N and lower contaminant level fed mostly on fish. The enrichment of δ13C increased with decreasing δ15N and lower contaminant levels. Therefore, individual behavior of great skuas, such as migration strategies and diet specialization, rather than long-range transport and thus baseline food web exposure, explain among and within colony variance in contaminant occurrence.

Outlier analyses to test for local adaptation to breeding grounds in a migratory arctic seabird

Investigating the extent (or the existence) of local adaptation is crucial to understanding how populations adapt. When experiments or fitness measurements are difficult or impossible to perform in natural populations, genomic techniques allow us to investigate local adaptation through the comparison of allele frequencies and outlier loci along environmental clines. The thick‐billed murre (Uria lomvia) is a highly philopatric colonial arctic seabird that occupies a significant environmental gradient, shows marked phenotypic differences among colonies, and has large effective population sizes. To test whether thick‐billed murres from five colonies along the eastern Canadian Arctic coast show genomic signatures of local adaptation to their breeding grounds, we analyzed geographic variation in genome‐wide markers mapped to a newly assembled thick‐billed murre reference genome. We used outlier analyses to detect loci putatively under selection, and clustering analyses to investigate patterns of differentiation based on 2220 genomewide single nucleotide polymorphisms (SNPs) and 137 outlier SNPs. We found no evidence of population structure among colonies using all loci but found population structure based on outliers only, where birds from the two northernmost colonies (Minarets and Prince Leopold) grouped with birds from the southernmost colony (Gannet), and birds from Coats and Akpatok were distinct from all other colonies. Although results from our analyses did not support local adaptation along the latitudinal cline of breeding colonies, outlier loci grouped birds from different colonies according to their non‐breeding distributions, suggesting that outliers may be informative about adaptation and/or demographic connectivity associated with their migration patterns or nonbreeding grounds.

On the polar edge: the status of the northern gannet (Morus bassanus) in the Barents Sea in 2015-16

ABSTRACTDuring its population recovery in the North Atlantic in the early 1900s, the northern gannet (Morus bassanus) established its first colony in Norway at Runde in 1946. Since the 1960s, gannets have established (and later abandoned) several small colonies in the north of the country. These colonies have been regularly monitored, and in 2015–16 ca. 3300 apparently occupied nests (AON) were counted in seven colonies in northern Norway. Two colonies that existed in 2008 had been abandoned and four new ones established. Two of the latter were again abandoned before 2015. In 1995, one pair established a colony at Kharlov on the Kola Peninsula, Russia, where numbers increased to 200–250 AON in 2016. The newest and world’s northernmost colony was established at Bjornoya (Bear Island) in 2011, extending the species’ breeding range well into the Arctic. These recent establishments are thought to be associated with a warming of the Barents Sea and the northward spread of common prey of the gannet such as herr...

Diet of a Nearctic Species, the Evening Bat (Nycticeius humeralis), at the Northern Edge of Its Range

Evening bats (Nycticeius humeralis) are ubiquitous in the southeastern United States, but only one maternity colony occurs in the Great Lakes region, in Michigan, and it is the northernmost colony known in North America. We hypothesized that diet would vary throughout the season and between years and that diet of evening bats in northern areas would differ from diet of those in more southern parts of the continent. Almost 600 fecal pellets of evening bats were collected and analyzed from May through August 2006–2007. Thirteen orders of insects and two orders of arachnids were found, but Coleoptera, Diptera, Hymenoptera, and Hemiptera composed 87% of dietary volume. Lepidoptera, which forms a substantial portion of the diet for most vespertilionids in eastern North America, contributed only 4.7% to the volume. Diet was broadly similar to evening bats in the core of their range, although evening bats in Michigan incorporated substantially more Diptera into their diet. Dietary composition and diversity differed little between years but showed variation among weeks within years. The lack of dietary specialization and similarity in major components in different parts of the range suggest that availability of prey or dietary competition with other species at the ordinal level are not factors limiting the northern distribution of the evening bat.

GENETICS AND DEMOGRAPHY OF KELP GULLS IN PATAGONIA

The Kelp Gull (Larus dominicanus), a common seabird in coastal Patagonia, has recently increased in overall abundance and distribution, creating some concerns for the protection and conservation of other native, threatened species. We combined genetic and demographic data of four large Kelp Gull colonies distributed along 1800 km of the northern Patagonian coast of Argentina to further understand patterns of population growth and migration of the species. DNA analysis of variable intron sequences of two separate genes (myelin proteolipid protein, β-fibrinogen) revealed similar intra-colony levels of DNA sequence diversity. Pairwise FST comparisons revealed significant differentiation of the northernmost colony, Islote La Pastosa, from the two southern colonies, Punta Tombo and Isla Vernaci Sudoeste (p < 0.05). Indirect estimates of gene flow suggest significant mixing among colonies (Nm > 6). Demographic estimates revealed that Islote La Pastosa showed an increase in the number of breeding individuals over time (λ = 1.075), representing an area of potential population expansion. This is consistent with previous studies that have suggested that the demographic connectivity among Kelp Gull colonies in Patagonia may follow a source-sink dynamics, where growth rates of growing colonies are fuelled by the immigration of individuals from nearby colonies. The observed pattern also reflects the overall expansion of the species in the Patagonian region. This study suggests that proper management strategies for the Kelp Gull should take into account the genetic and demographic dynamics of this species.

The decline of Norwegian kittiwake populations: modelling the role of ocean warming

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 60:91-102 (2014) - DOI: https://doi.org/10.3354/cr01227 The decline of Norwegian kittiwake populations: modelling the role of ocean warming Hanno Sandvik1,*, Tone K. Reiertsen2,3, Kjell Einar Erikstad1,3, Tycho Anker-Nilssen4, Robert T. Barrett2, Svein-Håkon Lorentsen4, Geir Helge Systad3, Mari S. Myksvoll5 1Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway 2Tromsø Museum, University of Tromsø, PO Box 6050 Langnes, 9037 Tromsø, Norway 3Norwegian Institute for Nature Research (NINA), FRAM - High North Research Centre for Climate and the Environment, 9296 Tromsø, Norway 4Norwegian Institute for Nature Research (NINA), PO Box 5685 Sluppen, 7485 Trondheim, Norway 5Institute for Marine Research, PO Box 1870 Nordnes, 5817 Bergen, Norway *Corresponding author: hanno@evol.no ABSTRACT: The black-legged kittiwake Rissa tridactyla is a pelagic seabird whose population has recently declined in most parts of the North Atlantic and which is red-listed in most bordering countries. To investigate a possible cause for this decline, we analysed the population dynamics of 5 kittiwake colonies along the Norwegian coast, ranging from 62° to 71°N, over the last 20 to 35 yr. By quantifying the importance of sea surface temperatures (SST) in relevant areas of the North Atlantic, we tested the importance of climatic conditions throughout the populations’ annual cycles. We found no synchrony among colonies; however, SST affected population dynamics, explaining between 6% and 37% (average 18%) of the variation in annual population growth rate. While dynamics of the southerly colonies were mainly affected by winter conditions in the Grand Banks area, dynamics of the northernmost colonies were dominated by autumn conditions off Svalbard. Negative slopes indicated stronger population decline under warmer ocean conditions. Population dynamics were affected both via adult survival and offspring recruitment, as evidenced by the presence of unlagged effects as well as effects lagged by the age at recruitment. Finally, we performed population viability analyses taking into account the projected warming trends for the future. The median time to extinction of the Norwegian colonies was 52 to 181 yr without considering covariates; 45 to 94 yr when considering the effects of SST but ignoring future warming; and 10 to 48 yr when ocean warming, based on a ‘business as usual’ scenario, was taken into account. KEY WORDS: Global warming · Non-breeding distribution · Population dynamics · Population viability analysis · Rissa tridactyla · Sea surface temperature Full text in pdf format Supplementary material NextCite this article as: Sandvik H, Reiertsen TK, Erikstad KE, Anker-Nilssen T and others (2014) The decline of Norwegian kittiwake populations: modelling the role of ocean warming. Clim Res 60:91-102. https://doi.org/10.3354/cr01227 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 60, No. 2. Online publication date: June 17, 2014 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2014 Inter-Research.

Regional variation in trophic ecology of adult female Australian sea lions inferred from stable isotopes in whiskers

Context The primary selective forces responsible for shaping life-history traits come from the physical and biological environment in which a species resides. Consequently, the limits of a species range may provide a useful measure of adaptive potential to environmental change. The proximity of foraging grounds to terrestrial nursing habitat constrains central-place foragers such as otariid seals in selecting breeding locations. The Australian sea lion (Neophoca cinerea) is an endangered otariid endemic to Australia, whose northern-range extent occurs at a temperate–tropical transition zone on the western coast of Western Australia (WA). Aims Currently, there is a complete absence of data on the foraging ecology of Australian sea lions in WA. We sought to address this critical knowledge gap and provide data on the foraging ecology of adult female Australian sea lions at three isolated breeding colonies in western WA. Methods We used stable-isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the whiskers of pups as proxies to characterise feeding behaviour of 10–28% of all adult female Australian sea lions at each colony. We then compared these geographic data to (1) conspecifics at similar latitude in South Australia (SA) and (2) isotopic data collated from other studies on seabirds that inhabit the region, to place foraging behaviour of adult female Australian sea lions into context. Key results At the southernmost colonies in WA, individual animals were members of one of two distinct isotopic clusters that could be described by differences in δ15N and δ13C values. Individuals at the northernmost colony displayed δ15N values similar to those of seabirds in the same region. Across the study, isotope ratios of adult female Australian sea lions in western WA were between 3‰ and 5‰ lower than those observed at a colony at similar latitude in SA. Conclusions Gross differences in the physical oceanography between WA and SA may in part explain the differences in isotope ratios of individuals between the regions, with lower δ15N and δ13C values in WA probably reflecting the relatively depauperate conditions of the Leeuwin Current. Implications Potential regional differences in trophic structure should be considered when developing appropriate management plans for Australian sea lions and regional variation in the diet of Australian sea lion warrants further investigation.

Breeding Phenology and Reproductive Success of the Brandt's Cormorant at Three Nearshore Colonies in Central California, 1997-2001

Brandt's Cormorant (Phalacrocorax penicillatus) breeding effort, phenology and success were studied in 1997-2001 at three colonies spanning approximately 200 km of the central California coast: Point Reyes (PR); Devil's Slide Rock and Mainland (DS); and Castle-Hurricane Colony Complex (CH). Breeding effort was reduced at all three colonies in the 1998 El Niño event. Mean clutch initiation dates differed significantly among colonies, with cormorants at the southernmost colony (CH) laying earliest, and those at the northernmost colony (PR) laying latest. Productivity at individual colonies varied greatly among years (range 0.7-2.5 fledglings per pair). Overall colony means were lowest (1.6 fledglings/pair) during the 1998 El Niño event and highest (2.5 fledglings/pair) in the 1999 La Niña event. Productivity at CH (1.7 fledglings/pair) was significantly lower than at PR (2.2 fledglings/pair), and interannual variation was greatest at CH. Late-nesting birds laid fewer eggs, hatched fewer chicks, and fledged fewer chicks per pair than early-nesters. The rapid rate of growth at some nearshore colonies in central California suggests immigration from elsewhere, most likely the large offshore colony at the South Farallon Islands. Variation in timing of breeding and reproductive success among colonies demonstrates a value in maintaining multiple study locations when assessing Brandt's Cormorant population parameters in the California Current System.

Regionally coherent trends in colonies of African penguins Spheniscus demersus in the Western Cape, South Africa, 1987–2005

From 1987 to 2005, numbers of African penguins Spheniscus demersus breeding in South Africa's Western Cape Province increased by about 50%. Numbers decreased at the four northernmost colonies in the region: Lambert's Bay and the three colonies in Saldanha Bay, although at Jutten Island the decrease is inferred from an estimate for 1987, derived from interpolation. Numbers also decreased at Geyser Rock and Dyer Island on the South Coast. At five colonies between Saldanha Bay and Dyer Island there were large increases. At a sixth colony in that region, Seal Island, where Cape fur seals Arctocephalus pusillus pusillus limit breeding space, numbers remained stable. At two colonies that were initiated in the early 1980s, Robben Island and Boulders, increases were initially rapid (>20% per annum) and matched growth of the South African stock of sardine Sardinops sagax. Strong growth at Dassen and Vondeling islands, between Robben Island and Saldanha Bay, was observed from about 1996–2002, when there was a large increase in the biomass of pelagic fish off South Africa. Increases at colonies between Saldanha Bay and Boulders slowed after 2002, whereas the colony at Dyer Island stabilised at that time. In 2003, a new colony was initiated east of Dyer Island at De Hoop Nature Reserve. These latter trends followed an eastward shift in the distribution of sardine. Small penguin colonies may act as foci for growth in a period when the distribution of prey is changing. Hence, it is important that they be maintained, especially those that, if lost, would increase the isolation of regional populations. Some of the small colonies are less susceptible to oil spills than colonies in the proximity of harbours, and for that reason also are important.

SUPERCOOLING OF THE RED IMPORTED FIRE ANT (HYMENOPTERA: FORMICIDAE) ON A LATITUDINAL TEMPERATURE GRADIENT IN TEXAS

Since its introduction into the United States, the imported red fire ant (Solenopsis invicta Buren), a freeze-intolerant species, has extended its range northward and now occupies areas where winter temperatures are consistently below freezing. The objective of our study was to determine if more northern S. invicta had greater supercooling capability than more southerly S. invicta. Such information would help to delineate the northern boundary of range expansion. We collected S. invicta colonies in early summer, late summer, and early spring from 3 locations along a latitudinal gradient in Texas. Supercooling point determinations were made immediately after colonies were collected and after colonies were acclimated in the laboratory for 1 and 2 months. Regardless of time or acclimation period, the northernmost colonies (−5.91 ± 0.21°C) had higher mean supercooling points than the southernmost colonies (−16.49 ± 0.11°C). Colonies from central Texas had intermediate mean supercooling points (−10.40 ± 0.19°C). This pattern is difficult to explain. Tests from a broader geographic range might allow us to better assess supercooling ability in S. invicta. Additionally, we tested whether supercooling points were affected by body size. We found no relationships between supercooling points and head capsule widths. However, there was little variation in head capsule widths of the minor workers that we measured. Differences in supercooling points might be evident only on a larger scale of body size.

Comments

Economia 3.1 (2002) 89-102 [Access article in PDF] Comments [Return to Article] Miguel Urquiola: In their paper, Engerman and Sokoloff summarize the results of a productive research program, undertaken with the broad objective of understanding why some former colonies in America have grown so much more than others, producing the dispersion of incomes seen today. In seeking to answer this question, they emphasize how different colonies' factor endowments conditioned the early and subsequent development of their institutions and thereby affected their readiness for modern industrial growth. This work is not only interesting in and of itself, but it has also served as a building block for recent influential research that extends these ideas to other regions of the world. 1 This note briefly summarizes the authors' argument and the facts they present and seek to explain. I then raise some identification issues and counterexamples that this work does not fully address, along with a couple of more specific issues to consider in future research. Some Interesting History That Needs an Explanation One of the key points that Engerman and Sokoloff seek to establish is that in the first century or two of European settlement in America, the southern English colonies (such as present-day Jamaica and the southern United States) and many of the Spanish colonies (such as Mexico and Peru) were just as well-off or even richer than northern colonies like the present-day northeastern United States or eastern Canada. 2 The large advantage in incomes that the latter have today did not begin to develop until the late eighteenth and nineteenth centuries. Engerman and Sokoloff were among the first to make this point and document its validity across the Americas, which is an important contribution in itself. This assertion has gained wide acceptance, and as [End Page 89] Acemoglu, Johnson, and Robinson show, such drastic changes in the relative wealth of former European colonies are also a feature in other parts of the world. 3 Accounting for the stark differences in growth experiences is the challenge that Engerman and Sokoloff face in their work. Their main emphasis is on the way colonies' factor endowments affected the development of their institutions, which in turn determined their readiness to take advantage of the industrial growth that started in the late eighteenth and nineteenth centuries. Put briefly, their argument is that in places such as the Caribbean or Brazil, soils and climate were suited to valuable crops with ample economies of scale, such as sugar, which stimulated the importation of slaves. This created a large, poor, and disenfranchised segment of the population. In other areas, like present-day Peru, the combination of factors like preexisting native populations, silver mining, and the awarding of large land holdings contributed to a similar outcome: highly unequal societies. While the value of sugar or silver made such colonies wealthy in their early history, the resulting economic and political inequality facilitated the formation of institutions that made these areas ill-suited for more modern economic growth. In contrast, the northernmost colonies, namely, the northeastern United States and eastern Canada, had soils best suited for the production of wheat and other grains, which presented few economies of scale. The authors contend that this led to their settlement by European immigrants working with relatively small landholdings. These colonies therefore developed more egalitarian societies and better institutions, which put them in a position to benefit more from industrial growth. A Strength in This Approach: Geography versus Institutions From an analytical perspective, this approach is interesting because it provides an alternative to pure geographical hypotheses, which assign responsibility for most differences in income to factors broadly related to geography. 4 As emphasized by Acemoglu, Johnson, and Robinson geographical explanations for economic performance generally suggest that differences in income should be quite persistent. 5 Engerman and Sokoloff, [End Page 90] however, show that something rather different is needed to account for differential paths of development in the Americas, and their argument outlines a theory that is consistent with the facts. In their theoretical outline, the key line of causality runs from factor endowments to poor institutions...

Nest Initiation and Clutch Size of Great Blue Herons on the Mississippi River in Relation to the 1993 Flood

Great Blue Heron (Ardea herodias) eggs were collected from ten colonies between Clinton, Iowa and Royalton, Minnesota on the Mississippi River in 1993, a year of record floods in the midwestern United States. In the five southernmost colonies where record flooding occurred, Great Blue Herons initiated nesting two weeks later than herons nesting in the five northernmost colonies that were less affected by flooding. The southern nests had a smaller average clutch size than the northern nests, but egg size was similar between south and north. Weather patterns in 1993 were similar between northern and southern colonies. We suspect that flooding of the available feeding habitat influenced nest initiation and clutch size. Data from 1995, a year without record flooding on the Mississippi River, support this hypothesis. In 1995, timing of nesting and number of eggs per clutch were similar between sites that had record flooding and sites that were less affected by flooding in 1993.

The dispersal and migration of the GannetSula bassanafrom Norwegian breeding colonies

This study is based on the recoveries of 72 Gannets ringed in the northernmost colonies in the world. Norwegian Gannets have the same dispersal and migration patterns as their British counterparts (Thomson 1974, Nelson 1978b, Veron 1988). During their first autumn, they move south into the North Sea, and on to waters off northwest Africa. Young birds probably remain in southern waters during their second summer. Older birds tend to move so far south.

The American Connection of Canadian Jews: 1759–1914

Its French and English antecedents notwithstanding, Canada is an American country. From 1759 to 1776 Canada was merely the fourteenth American colony of Great Britain. Had the fortunes of war been different, Canada might well have become part of the United States, or part or all of the United States might have remained British, joined with the northernmost colony. The Treaty of Paris made formal in 1783 the division between Canada and the other thirteen colonies, now independent. The treaty did not, however, put an end to the intimate cultural, economic and personal relationships, which had already developed among all North Americans of British origin. In fact, as time went on, those ties became closer, despite the border and despite the sometimes divergent political interests of the two countries. For Jews, that Canada was an American country was of considerable importance. By European standards, England was remarkably tolerant and open. With its vast economic potential, empty spaces, and society-in-the-making, however, America represented the real land of opportunity—economic and social—for all eighteenth and nineteenth-century Europeans, and especially for Jews.