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Simultaneous tetragyny in Northern Lapwing Vanellus vanellus

The Northern Lapwing Vanellus vanellus is usually regarded as a predominantly monogamous species (Glutz von Blutzheim et al. 1975, Cramp & Simmons 1983). Observations of trigyny were made by Rinkel (1940) and Wilson (1967). Recent studies conclude that polygyny is common in Lapwings (Berg 1993, Byrkjedal et al. 1997, Parish et al. 1997), and in all of these studies simultaneous trigyny was observed. To our knowledge, observations of simultaneous tetragyny in Lapwings have not been recorded previously. During a field study in southwestern Norway (Gimra, Sola, Rogaland), we observed a territorial male holding four females simultaneously. Observations were made from elevations surrounding the study area at minimum 100 m distance, or from a hide near the territory. All observations were made by using binoculars (10×) and a 15–45× telescope. Differences in plumage were used to distinguish individuals (see Byrkjedal et al. 1997). The male arrived and established territory on 13 March 1998 and began to court females that landed on or flew over his territory. Four females were present in the territory from 13 April until 8 May, a total of 26 days (Fig. 1). The females were simultaneously occupied with either laying eggs, incubating or tending chicks for a total of 11 days. On 19 April, all four were either incubating or egglaying. Mean egg-laying period for five clutches in the study area was 5.00 days (sd = ± 0.58), incubation starting at clutch completion. This concurs with the findings of Klomp (1951). Timing of the egg-laying period was estimated by backdating from hatching date, using an average incubation period of 26.16 days (sd = ± 1.03) for 25 females from the study area, all with known dates for completion of clutches and hatching. Female C was observed incubating from 2 April, but the nest was not checked before 5 April, then counting four eggs. Hence, clutch size from 2 April to 4 April is not known, and hypothetically the clutch could have been laid in this period. While the number of mates held simultaneBird Study (2001) 48, 124–125

Kin selection and polygyny: can relatedness lower the polygyny threshold?

Resource polygyny incurs costs of having to share breeding resources for female breeders. When breeding with a relative, however, such costs may be lessened by indirect fitness benefits through kin selection, while benefits from mutualistic behaviour, such as communal defence, may increase. If so, females should be less resistant to sharing a territory with a related female than with a non-related one. We investigated whether kin selection may lower the threshold of breeding polygynously, predicting a closer relatedness between polygynous females breeding on the same territory than between females breeding on different territories. Northern lapwings, Vanellus vanellus, are suitable for testing this hypothesis as they are commonly polygynous, both sexes take part in nest defence, and the efficiency of nest defence increases with the number of defenders. Using an index of relatedness derived from DNA fingerprinting, we found that female lapwings that shared polygynous dyads were on average twice as closely related as were random females. Furthermore, relatedness did not correlate with distance between breeders, indicating that our findings cannot be explained by natal philopatry alone. Our results suggest that the polygyny threshold in lapwings may be lowered by inclusive fitness advantages of kin selection.

Schools Taking Part in a Research Project Investigating Dioxins in Fish

The world is facing large environmental threats such as climate changes and spread of contaminants. Environmental awareness has become a part of our daily lives. In order to engage youth in environmental issues and ignite their interest for natural sciences, a scientifically based project was run where pupils participated in environmental research on dioxins in fish. Dioxins and dioxin-like PCBs were screened by the use of BDS DR CALUX® bioassay in 203 fish samples from 13 countries: Australia, Croatia, the Czech Republic, Denmark, Estonia, Finland, France, Iceland, Latvia, Liechtenstein, Norway, Poland and Sweden. The project was part of the Norwegian education and outreach initiative of the International Polar Year (IPY), and schools were invited to participate. Pupils from 54 schools followed a scientific protocol for fish sampling; they recorded and published important field and fish data through a Web interface and labelled, packed and shipped the samples for CALUX analysis. We conclude that collaboration between schools and research institutions was beneficial for both partners. The results showed that the majority of the fish samples had dioxin levels below the maximum limit set by the EU commission. These results would be difficult to obtain without the effort of the involved schools.

Rapid sampling of Males and Territories by Female Northern Lapwing, Vanellus vanellus

Abstract In many birds, females prospecting for high quality breeding resources have to inspect a number of males and their territories to make a good mating choice, yet in the face of competition with other females, the search time should be minimized. The sequential sampling of potential mates and territories by females is seldom witnessed. In a study of breeding Northern Lapwings, Vanellus vanellus, in Norway, we observed a female during the pair-formation period visiting seven territories in 105 mins, spending 15–20 mins on each of six territories pecking food from the ground and watching the resident male performing nest-scraping displays. One of the males was already mated, and on this territory the prospecting female spent only ∼2 mins. The observations show that female Northern Lapwings are potentially able to sample a high number of available territories in only a few hours.