Elliðaárdalur, Fossvogur, and the botanical garden in Laugardalur are places inside the city limits that are suited for bird watching. Other places worth mentioning are the mudflats at the Elliðaár-delta and at the Grafarvogur, Arnarvogur and Kópavogur inlets. All year round many sea bird species dwell along the coast around Reykjavík and vicinity. A rich birdlife can be observed at the Reykjavík Pond and in the marsh to the south of it which is the nesting site of many marshland bird species. Arctic terns, black-headed gulls, whooper swans and various duck species also nest on the holm in the pond. Just outside of the Reykjavík city limits is the community of Seltjarnarnes. On the outskirts of Seltjarnarnes there are untouched shores and, when the tide is out, it is possible to walk to the islet Grótta. Álftanes, to the south of Reykjavík, is a favourite spot among bird watchers. This is the nesting site of many birds, including arctic terns, eiders and other duck species, as well as marshland birds. Farther south along the coast, at the harbour of Hafnarfjörður, there are several species of ducks, marshland birds and sea birds. At Ástjörn and Urriðakotsvatn on the outskirts of Hafnarfjörður, Slavonian grebes may be observed in the spring and summer. They have become very sparse in the southwest of the country. Inland from the coast are the lakes Vífilsstaðavatn and Elliðavatn. Great northern divers nest annually at Elliðavatn.