"Don't put a carnivore in with a herbivore," cautions Richard Vinton as he distributes transparent plastic viewing pots to a group of Year 8 bug hunters. "Do that, and you might come back to find one less creature in your pot."
Richard, a trained conservationist, is a volunteer with Suffolk Wildlife Trust (SWT). He's helping run a pond-dipping activity at the trust's newest centre, Lackford Lakes near Bury St Edmunds. Two girls stand on the dipping platform swooshing long-handled nets through the water; others carefully empty their weedy spoils into shallow trays.
The students are engrossed, looking for signs of life and scooping damselfly nymphs, snails, leeches and cadisfly larvae into magnifying pots for closer inspection. Their finest examples end up in a viewing pool for the group to examine at the end of the session.
This is one of three outdoor activities the students from St Louis Middle School, Suffolk, take part in during the visit, the others being Birds and Trail (learning about bird behaviour and adaptation), and Walk on the Wild Side (a walk to experience the environment through art and drama).
The centre's education officer, Lorna Kerrison, says: "We offer plenty of activities based around the wildlife and habitats of the lakes and woodlands here and we're always keen to create programmes specifically for individual schools."
An example of this is the new bird trail, which was developed for St Louis's pupils to extend their bird-watching from earlier visits.
"The trail builds a more rounded appreciation of the birds, bringing in their habitat, their food, how their beaks are adapted to their diet, and so on," says Lorna Kerrison.
The centre offers many curriculum-linked activities, particularly for science and geography, and caters for all groups from pre-school to A-level. Visitors are usually aged between five and 13. The most popular activities are pond-dipping, bird-watching and the mini-beast hunt.
It's hard to imagine, seeing the tranquil reserve now, but Lackford Lakes was formerly a noisy gravel pit churning out gravel for road-building programmes. When quarrying finished in the late 1990s, owners RMC Aggregates gave 90 hectares to SWT and the reserve was born. Now its 220 acres have 12 lakes, a mixture of wet and dry woodland areas, reed beds, meadows and several bird hides. On this warm summer afternoon, the air is filled with bird song, flowers are bursting with colour, and geese are splashing on the lakes.
Lorna Kerrison says: "People tend to think of visiting the reserve during the spring and summer, but we guarantee you'll see wildlife in each season.
We have huge flocks of migratory birds all year round, and the lake-side paths and hides make watching animal and bird behaviour easy at any time."
Over lunch, the students swap their morning's experiences. Some talk of the sculptures and artworks they created from natural materials on the sensory trail, producing snakes from leaves pinned together with twigs. Others show sketches of the shelducks, herons, lapwings and crested grebes they've seen from the hides.
Judy Powell, education manager for SWT, enjoys hearing their excited conversations: "Part of what we want them to do is to have fun as they experience the environment. To love it and want to look after it, they have to enjoy it."
* Lackford Lakes is open Monday to Friday. Larger groups (up to 75): Monday and Tuesday; smaller groups Wednesday to Friday. Good wheelchair access.
Full-day admission: pre-school to key stage3 pound;3; KS4 pound;4; AS-level pound;5
ON THE SPOT
Gil Turner head of Maths, St Louis Middle School, Suffolk
This visit is part of the school's activity week, and my philosophy during this time is to free the children both from the national curriculum and the classroom, where every moment is governed by timetables and bells.
The students can simply experience, explore and discover. I think they learn just as much, although it may not be measurable. You only have to watch them pond-dipping, and see how excited they are by all those creatures that they didn't even know existed, to realise what their discoveries are teaching them.
If you asked them to fill out a worksheet, they wouldn't have the same feeling about it. The education team at the centre will develop new activities to suit your programme, and the activities link closely with many curriculum topics.
But they also link to life and help guide the children to an appreciation of what's around them. It's an amazing place, and the children get a lot out of their visits.
ON THE MAP
Suffolk Wildlife Trust, Lackford Lakes Reserve Centre,
Lackford, Bury St Edmunds, Suffolk IP28 6HX
Tel: 01284 728706