Procellariiform Birds Research Articles

Female and male Leach's Storm Petrels (Hydrobates leucorhous) pursue different foraging strategies during the incubation period.

Reproduction in procellariiform birds is characterized by a single egg clutch, slow development, a long breeding season and obligate biparental care. Female Leach's Storm Petrels Hydrobates leucorhous, nearly monomorphic members of this order, produce eggs that are between 20 and 25% of adult body weight. We tested whether female foraging behaviour differs from male foraging behaviour during the ~ 44-day incubation period across seven breeding colonies in the Northwest Atlantic. Over six breeding seasons, we used a combination of Global Positioning System and Global Location Sensor devices to measure characteristics of individual foraging trips during the incubation period. Females travelled significantly greater distances and went farther from the breeding colony than did males on individual foraging trips. For both sexes, the longer the foraging trip, the greater the distance. Independent of trip duration, females travelled farther, and spent a greater proportion of their foraging trips prospecting widely as defined by behavioural categories derived from a Hidden Markov Model. For both sexes, trip duration decreased with date. Sex differences in these foraging metrics were apparently not a consequence of morphological differences or spatial segregation. Our data are consistent with the idea that female foraging strategies differed from male foraging strategies during incubation in ways that would be expected if females were still compensating for egg formation.

The coracoscapular joint of neornithine birds\u2014extensive homoplasy in a widely neglected articular surface of the avian pectoral girdle and its possible functional correlates

A survey is given of the morphological variation of the coracoscapular joint of neornithine birds. In Mesozoic stem group representatives, the coracoid exhibits a deeply concave cotyla scapularis, which articulates with a globose tuberculum coracoideum of the scapula. This morphology is likely to be functionally related to the development of a powerful supracoracoideus muscle and the formation of a triosseal canal as a pulley for the tendon of this muscle. In neornithine birds, the coracoid articulates with the scapula either via a concave cotyla or a flat facies articularis, with the latter largely restricting movements of the coracoid to the paramedian plane. Ancestral state reconstruction suggests that a cotyla scapularis is plesiomorphic for Neornithes and that a flat facies articularis scapularis evolved at least 13 times independently within the clade. For several lineages, the transition to a flat facies articularis scapularis can be traced in the fossil record, and the replacement of a cup-shaped cotyla by a flat articular facet seems to have been due to various functional demands. Often, a flat facies articularis scapularis is associated with reduced shafts of the furcula. A weakly developed furcula enables transverse movements of the coracoid and therefore enables a restriction of the mobility of the coracoscapular joint to the paramedian plane. In taxa with a large crop, a flat facies articularis scapularis is likely to be associated with a reorganization of the pectoral musculature, whereas in procellariiform birds, the transition from a cotyla to a facies articularis appears to have been correlated with the capacity for sustained soaring without wing flapping.

New remains of the EoceneProphaethonand the early evolution of tropicbirds (Phaethontiformes)

A partial skeleton of the early Eocene tropicbirdProphaethon shrubsolei(Prophaethontidae) from the London Clay of Walton‐on‐the‐Naze (UK) is described. Most of the bones preserved in this fossil have not been described previously forProphaethonor prophaethontids in general. The pelvis and leg bones ofProphaethon, including the previously unknown tarsometatarsus, are very different from modern tropicbirds and show a strong similarity to procellariiform birds, especially albatrosses. Rather than employing plunge‐diving like their extant relatives, prophaethontids therefore probably used foraging strategies similar to those of modern albatrosses, which seize food on the sea surface. Prophaethontids also appear to have been less pelagic than extant tropicbirds, and these different life modes, as well as the disappearance of Phaethontiformes from northern latitudes, attest to major changes in Northern Hemispheric marine avifaunas during the Cenozoic, which also affected other pelagic birds. The reasons for the profound changes in the historical biogeography and way of living of tropicbirds are unknown, but ecological competition and predation at breeding sites are likely to have played a role.

Phylogenetic affinities and taxonomy of the Oligocene Diomedeoididae, and the basal divergences amongst extant procellariiform birds

The Palaeogene Diomedeoididae are amongst the earliest representatives of procellariiform birds (albatrosses, tubenoses, and allies). Although several fossils of these birds have been reported in the past, many details of their osteology remained unknown. Here we describe a comprehensive collection of diomedeoidid fossils from the Rupelian stratotype in Belgium, which was found more than 100 years ago. The material includes all major limb elements as well as other cranial and postcranial bones, and allows the recognition of previously unknown features of phylogenetic significance. Based on these new osteological data, diomedeoidids were for the first time subjected to a phylogenetic analysis, which resulted in a position outside a clade including Hydrobatidae (northern storm-petrels), Pelecanoididae (diving-petrels), and Procellariidae (fulmars, petrels, shearwaters, and allies), either as the sister taxon of Diomedeidae (albatrosses) or as that of all crown group Procellariiformes. The latter placement is better supported by the osteological evidence, and diomedeoidids lack several apomorphies of crown group Procellariiformes. Previously unrecognized derived features are reported that support a monophyletic Hydrobatidae, thus contradicting recent proposals that Oceanitinae (southern storm-petrels) are the earliest diverging crown group Procellariiformes. The new fossils also have a bearing on the convoluted taxonomy of diomedeoidids, and Diomedeoides Fischer, 1985 is synonymized with Rupelornis van Beneden, 1871. Diomedeoides lipsiensis (Fischer, 1983) is synonymous with Rupelornis definitus (van Beneden, 1871), a species that exhibits a large size range. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 854–875.

Anatomy of the coracoid and diversity of the Procellariiformes (Aves) in the Oligocene of Europe

Abstract: Two European species of the Diomedeoididae, an extinct family of procellariiform (tube‐nose) birds, have hitherto been distinguished primarily by size of their limb bones. Here, we describe an Early Oligocene (Rupelian) procellariifom coracoid that in all probability represents the larger species, Diomedeoides lipsiensis, and compare it to the coracoids of smaller diomedeoidids and extant procellariiforms. Using multivariate (Principal Component Analysis) and univariate analyses, we demonstrate that nearly all measurements are heavily size dependent, which makes the proportions and some other shape characters of little use as phylogenetic markers. Among eight measurements, the coracoid corpus width shows the highest correlation (higher than corpus depth) with body mass, permitting a precise calculation of over twofold difference in body mass between D. lipsiensis and smaller species. Among 16 qualitative characters analysed, the majority proved too variable to be used as markers of interfamily relationships and only 2–3, the ventral intermuscular line, sternocoracoid articulation (divided vs. undivided), and, with reservations, epimarginal crest vary consistently between the families. By far the most variable is the acrocoracoid process that tends to be deeper (more elongate dorsoventrally) in larger petrels but not in the albatrosses. However, the detailed shapes of the acrocoracoid heads are highly genus specific and suggest a genus‐level diversity among the Diomedeoididae from the Oligocene of Europe. The common features of the diomedeoidid coracoids are best interpreted as plesiomorphies, which accounts for some similarities to the Oceanitinae (that are probably basal among the crown‐group procellariiforms). The evidence from the coracoid is consistent with a stem‐group position of the Diomedeoididae as previously proposed by others. We emphasize the need of a group‐specific character analysis, primarily of allometries and levels of character variation, prior to a phylogenetic reconstruction.

Fatty acid signatures of stomach oil and adipose tissue of northern fulmars (Fulmarus glacialis) in Alaska: implications for diet analysis of Procellariiform birds

Procellariiforms are unique among seabirds in storing dietary lipids in both adipose tissue and stomach oil. Thus, both lipid sources are potentially useful for trophic studies using fatty acid (FA) signatures. However, little is known about the relationship between FA signatures in stomach oil and adipose tissue of individuals or whether these signatures provide similar information about diet and physiology. We compared the FA composition of stomach oil and adipose tissue biopsies of individual northern fulmars (N = 101) breeding at three major colonies in Alaska. Fatty acid signatures differed significantly between the two lipid sources, reflecting differences in dietary time scales, metabolic processing, or both. However, these signatures exhibited a relatively consistent relationship between individuals, such that the two lipid sources provided a similar ability to distinguish foraging differences among individuals and colonies. Our results, including the exclusive presence of dietary wax esters in stomach oil but not adipose tissue, are consistent with the notion that stomach oil FA signatures represent lipids retained from prey consumed during recent foraging and reflect little metabolic processing, whereas adipose tissue FA signatures represent a longer-term integration of dietary intake. Our study illustrates the potential for elucidating short- versus longer-term diet information in Procellariiform birds using different lipid sources.

Associations between chewing lice (Insecta, Phthiraptera) and albatrosses and petrels (Aves, Procellariiformes) collected in Brazil

Chewing lice were searched on 197 skins of 28 species of procellariiform birds collected in Brazil. A total of 38 species of lice were found on 112 skins belonging to 22 bird species. The lice were slide-mounted and identified. A list of lice species found and their host species is given and some host-louse associations are discussed under an evolutionary perspective.

New candidate species most closely related to penguins

The phylogenetic position of the order Spenisciformes in Aves remains unclear despite several independent analyses based on morphological and molecular data. To address this issue, we determined the complete mtDNA sequence of rockhopper penguins. The mitochondrial genome, excluding the region from the D-loop to 12SrRNA, was also sequenced for petrel, albatross, frigatebird, loon and grebe, which previous studies suggest are related to penguins. A maximum likelihood analysis of the phylogenetic placement of penguins with 23 birds, including 17 species whose mtDNA sequences were previously reported, suggested that storks are the closest extant relatives of penguins, with 78% and 56% bootstrap supports, depending on the choice of outgroup species. Thus, ciconiiform birds constitute new candidates as the closest extant relatives of penguins (previously proposed candidates were either gaviiform, podicipediform, or procellariiform birds). In addition to this new evidence, our analysis gave evidence to some of ambiguous relationships in the avian tree: our analysis supported a basal split between passerines and other neoavians within Neoaves, and rejected the monophyly of Falconiformes as well as that of loons and grebes.

Petrel-like birds with a peculiar foot morphology from the Oligocene of Germany and Belgium (Aves: Procellariiformes)

ABSTRACT New specimens of procellariiform birds are described from the Oligocene of Germany and Belgium, including a virtually complete and extraordinarily well preserved articulated skeleton. These birds show a peculiar foot morphology which to a striking degree resembles that of the recent Polynesian Storm-petrel Nesofregetta fuliginosa (Oceanitinae, Hydrobatidae). The pedal phalanges are dorso-ventrally compressed and especially the proximal phalanx of the fourth toe is grotesquely widened. The Oligocene Procellariiformes trenchantly differ, however, from Nesofregetta, the closely related genus Fregetta, and all other taxa of recent Hydrobatidae in the remainder of the skeleton. Possibly the feet served as a brake for rapid stops in order to catch prey, and we consider the similarities to Nesofregetta to be a striking example of convergence among birds. The specimens described in this study are referred to Diomedeoides brodkorbi, D. lipsiensis, and to Diomedeoides sp. The genus Frigidafons is a junior synonym of Diomedeoides, and Diomedeoides minimus is a junior synonym of Diomedeoides (= “Gaviota”) lipsiensis. An incomplete articulated specimen of Diomedeoides brodkorbi is of special taphonomic interest, since in the close vicinity of its left wing two fairly large shark teeth can be discerned which probably stuck in the soft tissues of the bird when it was embedded in the sediment.

Interactions between longline vessels and seabirds in Kerguelen waters and a method to reduce seabird mortality

Abstract A longline fishery for Dissostichus eleginoides has recently developed in the vicinity of South Georgia and Kerguelen islands, two internationally important breeding areas for procellariiform birds. The number of hooked birds and a method to reduce mortality were investigated during 13 days of fishing activity in Kerguelen waters in February 1994. Between 100 and 600 seabirds were always observed behind the longline vessel during daytime. The main ship-following species were the white-chinned petrel Procellaria aequinoctialis (67% of counts), giant petrels Macronectes spp. (8%) and the wandering albatross Diomedea exulans (11%), black-browed albatross D. melanophris (6%) and grey-headed albatross D. chrysostoma (2%). Only diving species were caught on the lines, i.e. the white-chinned petrel (n = 36) and the grey-headed albatross (n = 2). Marked differences in the mortality rate were observed between day and night (1·00 versus 0·38 birds per 1000 hooks), and at night when the decklights were on or off (0·59 versus 0·15 birds per 1000 hooks). Dumping of homogenized offal during line settings greatly reduced incidental capture of seabirds, mainly because birds were more attracted by offal than by hooked baits. We therefore propose that the dumping of offal during line settings should be included in the regulations of the longline fishery for Dissostichus in order to minimize seabird mortality.

Foraging Stochasticity and Lipid Accumulation by Nestling Petrels

1. Procellariiform birds accumulate large fat reserves during the nestling period; much of this is metabolized prior to fledging. We suggest that these energy reserves result from chronic overfeeding, which provides insurance against stochastic variation in food provisioning. 2. We develop a simulation model based on food provisioning and physiological measurements of Leach's storm-petrels and assess fat accumulation as a function of meal size. The simulations reveal that a level of food provisioning sufficient for accumulating, on average, the fat reserves of a typical fledgling results in the starvation of many chicks because of the chance occurrence of long periods of below-average feeding

Thermoregulatory abilities in chicks of the Antarctic Petrel (Thalassoica antarctica)

We studied the thermoregulatory capacity of Antarctic Petrel chicks, Thalassoica antarctica, breeding in a large colony in Queen Maud Land (71°53′S,5°10′E) on the Antarctic continent. Compared to newly hatched chicks of other birds, those of the Antarctic Petrel are characterized by a relatively high standard metabolic rate (SMR) and thermal conductance. Their metabolic scope is limited, however, being only 1.6 times the SMR, and they consequently depend on parental brooding to maintain Tb. At an age of 11 days the chicks become thermally independent and are left alone in the nest. The chicks keep a relatively high body temperature (>36°C) throughout their early development and we found no indication that they normally experience hypothermia. A significant positive relationship between latitude of breeding and SMR of the hatchlings is shown to exist for procellariiform birds. It is suggested that the high SMR found in Antarctic Petrel hatchlings could be a prerequisite for achieving a high growth rate, rather than being of any thermoregulatory significance.

Gastric Emptying and Gastrointestinal Motility in Leach's Storm-Petrel Chicks (Oceanodroma leuchorhoa)

-We used radiographic techniques to observe gastric motility during digestion of a meal in four Leach's Storm-Petrel chicks, 40-55 days old. A radio-opaque substance was added to the daily feeding for radiographic observation. We observed a biphasic gizzard contraction cycle with a frequency of 7.5 cycles/min. Gastric emptying occurred with each cycle and frequent intestinal refluxes were observed. Proventricular contractions were rarely observed; when observed, they affected only the ventral surface near the gizzard. Layering of proventricular contents, which we assumed to be a layer of dietary lipid over an aqueous phase, developed postprandially. Limited proventricular motility would favor layering; and ventral proventricular motility, along with regular gizzard motility, would promote gastric emptying of the more ventral aqueous layer. These observations are consistent with the idea that procellariiform are of dietary origin and that lipid accumulation in the stomach is linked to a unique gastrointestinal anatomy and motility. Received 21 March 1988, accepted 22 August 1988. PROCELLARIIFORM birds (albatrosses, fulmars, shearwaters, and other petrels) can store oil in their large, glandular and distensible fore-gut or proventriculus. The oil is found in both chicks and adults (Lewis 1966, Grubb 1971) and in birds captured at sea or on land. The oil was originally thought to be from the preen gland (Carter and Malcom 1927) or proventricular secretions (Matthews 1949), but is now considered to be of dietary origin (Imber 1976, Clarke and Prince 1976, Warham 1977, Jacob 1982). Cheah and Hansen (1970) proposed a mechanism for stomach oil formation in which low proventricular pH led to rapid breakdown of proteins and slow lipolysis, causing lipids to separate from the aqueous phase and accumulate. The heavy, more aqueous material settled and emptied first, followed by the lighter, oily lipid (Cheah and Hanson 1970, Warham 1977). This mechanism presumes that there is substantial layering of a lipid phase above an aqueous phase prior to proventricular emptying, and that the proventriculus must have limited gastric motility in order for the layering to persist. In humans, lipids empty from the stomach more slowly (14 ? 3% h-1) than aqueous (34.3 ? 1.8% h-W) or solid components (22 + 1.8% h-') (Jian et al. 1982), and some layering of lipids above nonlipids is found (Chang et al. 1968, Meyer et al. 1986). In birds, there are few studies that compare gastric emptying of lipid and aqueous components (Duke 1986a). Our objective was to describe for the gastric motility in a representative procellariiform. We specifically examined whether lipid accumulated above an aqueous phase in the proventriculus and whether a lack of motility in the proventriculus accounted for accumulation of oils. We chose Leach's Storm-Petrel chicks (Oceanodroma leucorhoa) as our representative procellariiform. The diet of Leach's StormPetrel chicks has a high (up to 60% of fresh mass) lipid content (Place and Roby 1986). We fed meals containing BaSO4 to storm-petrel chicks, and observed and recorded gastric motility cineradiographically. The observed gastric motility was considerably different than that previously described for other birds (Duke in press) and consistent with the accumulation of stomach oils in this species.

Light Attraction in Endangered Procellariiform Birds: Reduction by Shielding Upward Radiation

Autumnal attraction to man-made lighting causes heavy mortality in fledgling Hawaiian seabirds: Newell's Shearwater (Puffinus auricularis newelli), Dark-rumped Petrel (Pterodroma phaeopygia sandwichensis), and Band-rumped Storm-Petrel (Oceanodroma castro). These threatened, endangered, and rare species (respectively) approach and circle lights on their first flight from mountain nesting colonies on the island of Kauai to the sea. We shielded lights of the largest resort to prevent upward radiation on alternate nights during two fledgling seasons. Shielding decreased attraction by nearly 40%. Most attraction occurred 1-4 h after sunset. Full moon dramatically decreased attraction, a phenomenon that has both theoretical and management implications.

Egg Temperature and Embryo Metabolism in Some High-Latitude Procellariiform Birds

The embryos of Procellariiformes develop slowly, reportedly, at least in part, as a result of low incubation temperatures, and some species such as Wilson's and Leach's storm petrels experience long periods of chilling. Incubation temperatures of eggs of Leach's storm petrel (on Kent Island, New Brunswick), Wilson's storm petrel, and the southern giant fulmar (Palmer Station, Antarctica) averaged 35.9, 35.7, and 35.5 C, respectively. These are well within the range of temperatures for other species of birds and indicate that the prolonged incubation periods of petrels are not attributable to low incubation temperatures. We measured the depressing effect of cooling (Q10) on rate of heartbeat of small embryos and rate of oxygen consumption of larger embryos. Values of Q10 increased at lower temperatures but in most cases did not differ from, or in some cases even exceeded, the values for embryos of species that lack cooling tolerance. Large embryos of the giant fulmar, which has slow embryonic development but continuous incubation, did not survive prolonged chilling, indicating that not all slowly developing embryos tolerate protracted cooling, at least in their late stages of development. Rates of oxygen consumption by storm petrel embryos were about two-thirds the level of the similarsized but rapidly growing Japanese quail embryo. Giant fulmar embryos exhibited low rates of oxygen consumption, as do other Procellariiformes, but, surprisingly, so did the rapidly growing skua embryos.

The Composition of Petrel Eggs

-Examination of fresh eggs from 23 species of procellariiform birds shows that the relative amounts of albumen and yolk in the egg depend upon egg size, large eggs having proportionately more albumen and less yolk than smaller ones. Similar allometric relationships also exist within two species, Diomedea immutabilis and Puffinus griseus. The proportions of these components in eggs differ from those in the eggs of either precocial or altricial birds in general. The yolk in eggs lighter than 25 g weighs more than that in eggs of similar size produced by typical precocial birds. Shell weight is a relatively constant percentage of egg weight, except for fulmars, which nest among rocks and on ledges: their eggs have heavier and thicker shells than other eggs of similar size. Heinroth (1922) pointed out that the eggs of altricial birds contain less yolk than those of precocial birds. The yolk reserves carried by the hatchlings in their yolk sacs are also generally larger in precocial birds than in altricial ones of similar body weights. Ar and YomTov (1978) calculated that, on average, precocial hatchlings have twice as much yolk as altricial ones. Romanoff and Romanoff (1949) compiled data on the weights of egg components with respect to the weights of intact eggs. These may be summarized: Altricial species-yolk 12-27%; albumen 6879%; shell 5-10%. Precocial species-yolk 32-41%; albumen 51-56%; shell 9-14%. They pointed out that the proportions of yolk, albumen, and shell vary with the size of egg in both altricial and precocial species, larger eggs having relatively smaller yolks, larger whites, and heavier shells than small eggs. They also noted, as had Curtis (1912), that similar size-related differences in the egg's constituents exist intraspecifically in the domestic fowl (Gallus gallus, var. domesticus). The study of the egg's contents has been stimulated recently because of its importance to the energetics of parental care and developmental processes (see, for example, Lack 1968a, b, Ricklefs 1977, Ar and Yom-Tov 1978, Carey et al. 1980). In uncovering basic relationships between the egg, its producer, and its product, the order Procellariiformes has special characteristics that may make it particularly useful. First, the group is monophyletic; second, its members exhibit a great range of body weight from about 20 g in the Least Storm-Petrel (Halocyptena microsoma) to about 8,700 g in the Royal Albatross (Diomedea epomophora); and third, the clutch of all the species consists of only one egg. Despite these advantages, little information is available about the constituents of the eggs of albatrosses, shearwaters, and other petrels. I this paper, I report the yolk, albumen, and shell weights for eggs of 23 members of this order, including the southern fulmarine species Macronectes giganteus, Fulmarus glaci loides, Daption capense, and Pagodroma nivea previously studied by Etchecopar and Prvost (1954). The study was undertaken (1) to test the hypothesis that the proportions of the constituents of the eggs vary in a regular manner among procellariiform species according to the size of their eggs, (2) to seek anomalies requiring further examination, and (3) to determine if the intraspecific trends noted by the Romanoffs in the fowl also exist among petrels. (In this paper, petrel is used as a general term for any procellariiform bird.)

Comparison of the feeding apparatus in the muttonbird, Puffinus tenuirostris (Temminck) and the fairy prion, Pachyptila turtur (Kuhl) in relation to the capture of the krill, Nyctiphanes australis sars

Abstract The short-tailed shearwater (muttonbird) Puffinus tenuirostris (Temminck) and the fairy prion Pachyptila turtur (Kuhl) are procellariiform birds which feed extensively on the euphausiid Nyctiphanes australis Sars in south eastern Tasmania. Data from a hydrodynamic study of the heads of the two birds were used to develop a simple qualitative model of food capture. This model predicts that as the bird moves through the water the open gape, aided by the bill architecture, produces and maintains a low pressure volume into which the prey is sucked. Once inside the bill euphausiids are prevented from escaping by filtering systems which differ in the two birds. In the muttonbird, the filtering mesh consists of retroverted papillae of the upper palate which overlap with opposing papillae on the tongue. In the fairy prion a combination of papillae in the oral cavity and a series of closely-set lamellae on the margins of the upper palate serve to retain the krill.

Embryonic Double Monster in the Wedge-Tailed Shearwater

During a study of embryonic respiration in the Wedgetailed Shearwater (Puffinus pacificus), an egg was collected and found to contain an embryonic duplicitas: a double monster or Siamese twin. This egg was collected on 7 August 1979 from Manana Island, Oahu, Hawaii and was 40 + 1 days old; the incubation period for this species averages 52 days. After respiratory data had been obtained, the egg was dissected and a double-monster embryo was found inside. The body of the embryo was completely duplicated except for a common head with one eye absent and the brain exposed on the left side. This embryo conformed to Ulshafer and Clavert's (J. Embryol. Exp. Morphol. 53:237-243, 1979) Group I classification of avian double monsters. The yolk-free mass of the abnormal embryo (10.3 g) equalled 47% of the yolk-free mass of normally developed shearwater embryos of the same age. The incidence of malformation in Wedge-tailed Shearwaters is difficult to assess but in 170 eggs we have examined over a three-year period, this is the first embryonic anomaly found. This would place the incidence of malformation at 0.59%. Romanoff (Pathogenesis of the avian embryo, John Wiley and Sons, 1972) reported values of 0.8% to 0.06% for embryonic duplicitas in chicken eggs. In ducks the phenomenon is more common: about 2% of all fertilized eggs form double monsters. The effect is believed to be caused by changes in orientation of the egg within the shell gland during the critical period of symmetrization, resulting in the formation of two organizing centers (Ulshafer and Clavert 1979). Other teratogenic factors may include high levels of pesticides and mercury. Fisher (Pac. Sci. 27:220-225, 1973) reported high levels of toxic substances in the Laysan Albatross (Diomedea immutabilis) on Midway Atoll but we know of no such stu ies on other procellariiform birds. This study was supported in part by the National Science Foundation (Grant #PCM-12351-AO1 to G. Caus y Whittow) and the Leahi Trust Fund, Research Corporation of the University of Hawaii (Grant #1979 to Ted N. Pettit).

Olfactory Guidance in Foraging by Procellariiforms

Systematic field experiments show that procellariiform birds, viz., Black-footed Albatrosses (Diomedea nigripes), shearwaters (Puffinus griseus, P. creatopus, P. puffinus, P. bulleri, and P. tenuirostris), Northern Fulmars (Fulmarus glacialis), and storm-petrels of several species, are consistently attracted to sources of food-related odors under natural conditions at sea with controlled visual cues. They approach predominantly from down-wind, in proportions above control levels, when food odors are presented as surface slicks, slicks spread in large shallow pools of plastic floating on the ocean, and by saturated wicks on free-floating rafts. Control stimuli and odorous materials unrelated to food do not attract procellariiforms. Birds of other orders are not attracted by any odorous stimulus, and approach the areas from all directions only when discrete visual stimuli are added. Observations and photographs reveal a flight pattern displayed only by procellariiforms in their apparent foraging approaches to food-related stimuli. Tube-nosed birds are most numerous under conditions of reduced visibility, high winds, large swells, and turbulent ocean surface. The results of this study strongly support the view, previously based on comparative anatomy and uncontrolled observations, that procellariiforms use olfaction in locating food.

Egg Neglect in the Procellariiformes: Reproductive Adaptations in the Fork-Tailed Storm-Petrel

The eggs of many procellariiform birds may still hatch even though temporarily abandoned during the incubation period. Distant foraging and long incubation periods, characteristic of these birds, increase the probability that storms or undependable food resources will delay an individual's returning to relieve its incubating partner. Consequently, tolerance to chilling by the embryo has evolved to a greater degree in the Procellariiformes than in other orders. This paper reports the incidence of egg neglect in the Fork-tailed Storm-Petrel (Oceanodroma furcata), and discusses the adaptive significance and costs of egg neglect in the Procellariiformes.