Winged insects including bees, moths and butterflies are suffering this year following the UK's late, cold spring, a National Trust report has revealed.
The charity warns the drop in numbers of winged insects could lead to food shortages for birds and bats.
The six-month review assessed the state of plants and animals in England, Wales and Northern Ireland and came up with a "winners and losers" list.
Snowdrops, bluebells and daffodils are all on the winners' list
Among the "losers", butterflies have been "very scarce" this year, due to a combination of an unsettled spring and the last year's extremely wet summer.
Likewise, moth numbers have been driven down by cool, wet or windy nights over the past few months.
Mason bees and mining bees also struggled to survive in poor weather in May, which may have a knock-on effect for plant pollination.
"Insect populations have been really very low. Then when they have got going, they've been hit by a spell of cool, windy weather... so our environment is just not bouncing with butterflies or anything else," said Mathew Oates, a naturalist at the National Trust, who worked on the report.
He acknowledged insects follow a "boom and bust pattern", but explained: "The concern is when you have a sequence of poor summers, then a lot of small [insect] populations are lost... and they [effectively] retreat back to the nature reserves."
Birds on the "losers" list include martins, swifts, swallows and warblers, all of which rely on airborne insects to feed and may struggle to survive in the coming months.
Some seabird populations have been hard hit too. In March, windy weather along the coast of Scotland and northern England led to the apparent starvation of thousands of puffins along with guillemots, razorbills, kittiwakes and shags.
However, a number of animals and plants have enjoyed a more fruitful year, earning a place on the list of "winners" of the first half of 2013.
Snowdrops and daffodils had "amazingly long flowering seasons", according to the charity, with daffodils flowering well into May and snowdrops appearing from January through to mid-April.
And the weather has not been problematic for all birds: rooks are less sensitive to poor conditions than other birds and 2013 has so far been a "superb" year for the animals, following reports of a very successful breeding season.
Mr Oates said: "This year winter was loath to let go. All of this has meant that spring got seriously behind and was the latest since 1966."
The delayed spring, beginning with the coldest March in 50 years, meant frogs and toads struggled to breed in water that was still frozen and many flowering plants in gardens and in the wild such as dogwood, elder and lilacs, bloomed weeks later than normal.
Mr Oates said that people and wildlife alike in Britain are now "crying out for a long hot summer."
"Summer is now running two to three weeks late but may come good yet."
Speculating ahead to the second part of 2013, the National Trust predicts a good year for cabbage white butterflies which appear in July and August. Late-flowering apple varieties are also expected to be abundant following some good weather for pollination in early June.