Flora and Fauna along the brook
In 2017, in the first of a ten-year assessment of wildlife in Hobson’s Brook, more than 40 experts and 160 volunteers in ‘The Hobson’s Conduit Bioblitz’ have identified over 330 animal and plant species along this four-mile stretch of water.
At Nine Wells Local Nature Reserve, 166 species were identified including 35 birds, 5 mammals, 2 fish, 50 invertebrates (including 30 moths) and 74 plants. At Empty Common over 230 species were seen including 17 birds, 4 mammals, 2 fish, 1 reptile, 106 invertebrates (39 moths) and 103 plants. Importantly only 76 species were common to both sites indicating considerable diversity along Hobson’s Brook. This study confirms the importance of maintaining high-quality water flow in the continued success of this ecosystem so close to Cambridge city.
For detailed lists of flora and fauna recorded, please read the latest report below. This section of the website also shows some of the plant and animal species seen along the water course.
Water Voles (Ratty from Wind in the Willows) are found along the whole water course. They are a similar size to brown rats, but have rounder faces, darker fur and smaller ears. Water Voles dig burrows close to the water’s edge and nibble vegetation along the banks and are a protected species. Image: Peter Trimming
Perhaps the most ubiquitous species at all times of the year. Several pairs breed, and family parties can be seen in summer all along the Brook and have even be seen crossing Trumpington Street. Image: Garth Peacock
Grey Herons can be seen along the upper reaches of the Brook at any time of year. The nearest breeding colony is near where Vicar’s Brook makes its outfall into the River Cam at Sheep’s Green. Image: Garth Peacock
Increasingly frequent along the upper reaches, with up to six Little Egrets have been seen together in the winter. As of 2018, no breeding has been established, but as this species continues to expand its range, that cannot be far off. Image: Garth Peacock
Snipe feed in winter along the muddy edges of the Brook and its feeder ditches. Snipe are usually only seen when it flies away with its zig-zag flight and heard as a result of its harsh call. Image: Garth Peacock
A common species along the Brook at all times of year. Several pairs nest, and adults can be seen feeding young in many places, often along the most public stretches beside the University Botanic Garden and Brookside. Image: Garth Peacock
Kingfishers hold winter territories along the Brook, and can be seen perching on bankside vegetation or flying, like bright blue bullets, low over the water. Kingfishers have previously albeit occasionally nested along the upper reaches. Image: Garth Peacock
With more Common Reed (Phragmites australis) in the watercourse, Reed Warblers are increasingly common in summer. Cutting back the reed in winter tries to limit growth each year, which can obstruct water flow. Image: Garth Peacock
The reed bunting nests in varied vegetation both in the stream and along the banks and adjoining ditches. It is present all year round, sometimes in flocks of up to twenty birds in winter. Image: Garth Peacock
Seen in winter along upper reaches of the Brook, the grey wagtail may be heard before being seen, because of its ‘chi-chic’ flight call. Grey wagtails have attempted to nest in the past - human disturbance makes this less likely. Image: Garth Peacock
Frogs are smooth brown or grey and have long back legs. They live in garden ponds laying eggs as spawn in spring, spending the rest of the year feeding on terrestrial invertebrates in grassland and smaller amphibians. Frogs jump rather than walk and females are bigger than males. Image: Richard Bartz
Three spined sticklebacks can reach a length of 50 mm. and are very common all along the whole brook with shoals seen throughout the year. Midge larvae and chironomids are the main food sources. Breeding starts in April when the brightly coloured males become very territorial. Image: Gerard/Ron Offermans
Ten spined sticklebacks are less common and more secretive than the three spined variety and paradoxically can have between eight and twelve spines. This species is occasionally seen along the whole length of the brook. Ten spined sticklebacks are up to 50mm long, but can occasionally grow larger. Image: Piet Spaans
The Stone Loach is the largest of the fish commonly found in the brook reaching a maximum length of 140 mm. They are nocturnal and solitary, living in areas of sand or gravel, feeding on mayfly larvae and small invertebrates often at the bottom of the stream. Stone Loaches use the barbels near the mouth to detect their food.
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