| 1. |
- Myrberg Burström, Nanouschka, 1969-
(författare)
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The Hatched Cross : Gotlandic Coins of the 13th century Baltic Sea area
- 2012
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Ingår i: Monetary History of the Baltic in the Middle Ages (12-16<sup>th</sup> C.). - Tallinn : Eesti Ajaloomuuseum. ; , s. 180-196
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Bokkapitel (refereegranskat)abstract
- In the 12th century, some authority on the island of Gotland in the Baltic Sea started off a coinage, the first ever on Gotland and the first medieval coinage of Sweden as a whole. Quite remarkably, these and any following coins minted on the island never adjusted to the Swedish mainland royal coins in weights or iconography, but seem to have been independently administered even though the island was within Swedish power (for any period when it was not under somebody else’s control). In the 12th century and well into the 13th, Gotlandic coins had a strong impact on certain areas of the mainland, and in the 13th century they were even used as a model for new coinages in the Baltic Sea area. Interestingly, these first Gotlandic coins in several ways show where their inspiration came from, and thus perhaps who or what motivated their coming into being: trading partners and other guests from the southwestern parts of the Baltic and North Sea.
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| 2. |
- Bengtsson, Hans, et al.
(författare)
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Development of Parent‐Young Interaction in Asynchronously Hatched Broods of Altricial Birds
- 1981
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Ingår i: Zeitschrift fuer Tierpsychologie / Journal of Comparative ethology. ; 56:3, s. 255-272
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Tidskriftsartikel (refereegranskat)abstract
- In bird species which have developed a brood reduction strategy, initial inequality among siblings is established through asynchronous hatching. After hatching, the maintenance of a weight hierarchy within the brood and its spread is governed by the allocation of feeds to the chicks and by the rate of parental feeding. In the present study, the initiation of parental feeding and subsequent changes in the feeding procedure were studied in asynchronously hatched broods of the great tit Parus major and the blackbird Turdus merula. During the period of hatching the brood was roused by a parental feeding call on most visits to the nest which made feeding niore effective. Late-hatched young initially increased their chances to receive feeding offers by showing a high rate of spontaneous begging. In addition, they were more dependent than the older young on a high rate of mobility in order to be fed and they showed increasing mobility with age. Crucial changes in the feeding procedure took place at the end of the hatching period when the parents ceased to emit feeding calls and in the last few days before the abandonment of the nest when the biggest young started to jump towards the parents at feeding. These periods were identified as critical for late-hatched young. We argue that parental feeding rate is a feature of parent-young interaction that develops in order to adapt parental investment in individual nestlings to changes in food conditions when the brood is being raised.
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| 3. |
- Rydén, Olof, et al.
(författare)
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Differential begging and locomotory behaviour by early and late hatched nestlings affecting the distribution of food in asynchronously hatched broods of altricial birds
- 1980
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Ingår i: Zeitschrift fuer Tierpsychologie / Journal of Comparative ethology. ; 53, s. 209-224
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Tidskriftsartikel (refereegranskat)abstract
- Distribution of food to early and late hatchcd nestlings was studied in asynchronously hatched broods of the grr,it tit P~rcrs major, the blackbird Turdus mcrula, and the fieldfare T. pilaris. Food distribution is related to the locomotory and begging behaviour and positions in the nest of these nestlings. Late hatched (small) nestlings were found to beg more often per feed than bigger nectlings and move more towards favoured positions in the nest to counteract selective feeding of bigger young. The functional significance of these differences in the behaviour of early and late hatched nestlings are discussed. It is argued that they are adaptive by 1) ensuring that each nestling survives when food supplies are ample, and 2) by mediating an optimal brood reduction when food is insufficient to raise the entire brood. The roles of asynchronous hatching, and selective feeding which follows from differential behaviour of early and late hatchcd young are discussed in relation to food conditions during the breeding season.
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| 4. |
- Fängström, Britta, et al.
(författare)
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Hydroxylated PCB Metabolites in Non-hatched Fulmar Eggs from the Faroe Islands
- 2005
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Ingår i: Ambio. - : Allen Press. - 0044-7447 .- 1654-7209. ; 3:34, s. 184-187
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-six polychlorinated biphenylols (OH-PCBs) conge-ners were characterized in Fulmar (Fulmarus glacialis) eggs collected from the Faroe Islands. The seven most abundant congeners were quantified in 19 samples, and the XOH-PCB concentrations ranged between 0.92 and 4.0 ng g 1 fresh weight (f.w.). These eggs constitute a part of the traditional diet for at least a part of the population on the Faroe Islands and may contribute to the high levels of these contaminants found in the blood of pregnant Faroese women. Because the metabolites are present in the nonhatched fulmar egg, it is concluded that the OH-PCBs are transferred to the egg before laying. High levels, 3300- 18 000 ng g-1 l.w., of 2polychlorinated biphenyls (PCB) were determined in the fulmar eggs, which are a consider-able source for human exposure. The high PCB levels are a source for metabolic formation of hydroxylated PCBs.
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| 5. |
- Sundström, L. Fredrik, 1972, et al.
(författare)
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Hatchery selection promotes boldness in newly hatched brown trout (Salmo trutta): implications for dominance
- 2004
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 15:2, s. 192-198
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Tidskriftsartikel (refereegranskat)abstract
- By using newly hatched (approximately 2 weeks old) brown trout (Salmo trutta) from six families of wild and six families of sea-ranched origin (seventh generation), we tested the hypotheses that (1) the hatchery environment selects for increased boldness, and (2) boldness predicts dominance status. Sea-ranched trout spend their first 2 years in the hatchery before being released into the wild at the onset of seaward migration. Trout were presented with a novel object (tack) and with food (brine shrimp), and their responses were measured and scored in terms of boldness. Siblings with increasing difference in boldness were then paired in dyadic contests. Fish of sea-ranged origin were on average bolder than were fish of wild origin, and bolder individuals were more likely to become dominant regardless of origin. Boldness was not related to RNA levels, indicating that bold behavior was not a consequence of higher metabolism or growth rate. Neither was size a predictor of bold behavior or the outcome of dyadic contests. These results are consistent with studies on older life stages showing increased boldness toward predators in hatchery-selected fish, which suggests that behavioral consequences of hatchery selection are manifested very early in life. The concordance between boldness and dominance may suggest that these behaviors are linked in a risk prone-aggressive phenotype, which may be promoted by hatchery selection. However, we also found significant variation in behavioral and growth-related traits among families, suggesting that heritable variation has not been exhausted by sea-ranching procedures.
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| 6. |
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| 7. |
- Bengtsson, Hans, et al.
(författare)
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Parental feeding rate in relation to begging behavior in asynchronously hatched broods of the great tit Parus major: An experimental study.
- 1983
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Ingår i: Behavioral Ecology and Sociobiology. - 1432-0762. ; 12:3, s. 243-251
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Tidskriftsartikel (refereegranskat)abstract
- Four experiments manipulated the stimulus situation encountered by great tits on their feeding visits to the brood in order to explore its effect on feeding rate. Three broods containing 8, 8, and 10 nestlings were studied. A higher feeding rate was observed under the following conditions: (1) after a period of food deprivation, as compared with normal conditions and satiation through artifical feeding; (2) in periods when recorded begging calls were played during feeding visits, as compared with control periods; and (3) after temporary removal from the nest of heavier, as compared with lighter, siblings. The lighter nestlings benefitted more (in terms of weight gain) from the increase in parental feeding rate following the playing of begging calls than did the heavier nestlings. Differences in weight within broods did not affect the amount of food the parents brought. It is concluded that parental feeding rate is affected not simply by the begging of the hungriest nestling but rather by the behavior of all the nestlings, which makes possible an adjustment of the feeding rate to the average hunger level of the brood.
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| 8. |
- Boyner, Malin, et al.
(författare)
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Effect of hatching time on time to first feed intake, organ development, enzymatic activity and growth in broiler chicks hatched on-farm
- 2021
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Ingår i: Animal. - : Elsevier BV. - 1751-7311 .- 1751-732X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- The conventional commercial hatcheries used today do not allow the newly hatched chicks to consume feed or water. Combined with natural variation in hatching time, this can lead to early hatched chicks being feed-deprived for up to 72 h before being unloaded at the rearing site. This study investigated the effects of hatching time on time to first feed intake and development of organs, digestive enzymes and productivity in terms of growth and feed conversion ratio in chicks hatched on-farm. Chicks were divided into three hatching groups (early, mid-term and late), and assessed over a full production cyde of 34 days. The results revealed that chicks remain inactive for a considerable amount of time before engaging in eating-related activities. Eating activity of 5% ( i.e. when 5% of birds in each hatching group were eating or standing dose to the feeder) was recorded at an average biological age (BA) of 25.4 h and a proportion of 50% birds with full crop was reached at an average BA of 30.6 h. Considering that the hatching window was 35 h in this study, the average chick probably did not benefit from access to feed and water immediately post-hatch in this case. At hatch, mid-term hatchlings had a heavier small intestine (30.1 g/kg bw) than both early (26.4 g/kg bw) and late (26.0 g/kg bw) hatchlings. Relative length of the small intestine was shorter in late hatchlings (735 cm/kg bw) than in mid-term (849 cm/kg bw) and early (831 cm/kg bw) hatchlings. However, the relative weight of the bursa fabridi was greater in mid-term (130 g/kg bw) than in early hatchlings (1.01 g/kg bw). At hatch, late hatchlings were heavier than early and mid-term hatchlings (P < 0.05), but by 3 days of age early hatchlings were heavier than mid-term and late hatchlings (P < 0.01). The only effect persisting throughout the study was a difference in the relative weight of the small intestine, where late hatchlings had heavier intestines than early hatchlings (P < 0.05). Thus, while there were differences between hatching groups, this study showed that the hatchlings seemed capable of compensating for these as they grew. (C) 2020 The Authors. Published by Elsevier Inc. on behalf of The Animal Consortium.
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| 9. |
- Oddie, KR
(författare)
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Size matters: competition between male and female great tit offspring
- 2000
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Ingår i: JOURNAL OF ANIMAL ECOLOGY. - : BLACKWELL SCIENCE LTD. - 0021-8790. ; 69:5, s. 903-912
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Tidskriftsartikel (refereegranskat)abstract
- 1, Studies of sex allocation in birds have traditionally centred on Fisher's (1930) theory of equal parental investment in male and female offspring. They concentrate particularly on sexually dimorphic species, where costs of rearing offspring are assumed
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| 10. |
- Nilsson, J. A.
(författare)
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Causes and consequences of natal dispersal in the marsh tit, Parus palustris
- 1989
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Ingår i: Journal of Animal Ecology. - : JSTOR. - 0021-8790. ; 58:2, s. 619-636
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Tidskriftsartikel (refereegranskat)abstract
- Dispersal distance, measured as the number of territories between place of birth and place of first breeding, was analysed within and between sexes in juvenile marsh tits in relation to factors potentially caiusing variation in dispersal pattern. Dispersal distance of males was positively influenced by both population density and hatching date. In females, dispersal distance were positively related to population density, number of siblings and wing length. Early-hatched females dispersed further than those hatched in the middle of the season. Dispersal distance in females was positively related to the number of recruits among their offspring. Females surviving for more >1 breeding season had dispersed further as juveniles than females breeding only once. In males, dispersal distance did not affect survival or breeding success. Males are severely affected by the density of already established individuals, and have no time to choose flock ranges according to quality. Thus, males try to become established as soon as possible after independence. Late-hatched males disperse further and are less successful at establishing themselves than early-hatched males. Females, especially those hatched early, more easily become established and can afford to monitor several flock ranges and to be selective in their choice of flock range. This selectivity results in long dispersal distances for early-hatched females and a high lifetime reproductive success for long dispersers. -Author
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