How bird and bat deaths can ripple into insects, crops, and daily life

Wind turbines kill birds and bats.

That part is already in the public debate.

What gets ignored is my next question:

What happens after we remove insect-eaters from a landscape?

Here, I use published ranges and simple math to show a cascade chain you can measure.

The chain in one line

Wind turbines kill birds and bats → fewer insect predators → more surviving insects → more crop damage and more spraying → higher costs and lower quality of life.

Step 1: How many birds and bats are we talking about?

Published estimates put U.S. wind-turbine bird deaths around 234,000–368,000 per year (Loss 2013; Erickson 2014).

For bats, estimates vary by region and method, from tens of thousands to hundreds of thousands. Some North American summaries discuss totals that may exceed 1 million in a given year.

These are published ranges.

Step 2: How many insects did those animals eat?

Birds and bats are insect predators. They do pest control for free.

A global estimate indicates that insect-eating birds consume 400–500 million metric tons of insects annually (Nyffeler 2018). That shows the scale of what birds do.

For bats, I use common intake anchors: 4–8 grams of insects per night, and about 200 active nights per year. Boyles et al. (2011) also give a scaling anchor: removing 1 million bats corresponds to 660–1,320 metric tons of insects not consumed.

Step 3: I use conservative math to estimate “insects not eaten”

Birds

I use this conservative setup:

• 300,000 birds/year
• 12.5 grams/day
• 180 days

That equals about 675 metric tons per year of insects not eaten.

Bats

If turbine-related bat deaths are 1,000,000/year, I use:

• 6 grams/night
• 200 nights

That equals about 1,200 metric tons per year of insects not eaten.

That also fits inside the Boyles range (660–1,320 tons) for 1 million bats.

Combined

Birds (~675 tons) + bats (660–1,320 tons) give about:

~1,300–2,500+ metric tons of insects per year not consumed under conservative assumptions.

That is the scale of the biological control I am removing.

Step 4: What do those extra insects do?

They do not just “exist.” They bite, feed, reproduce, and spread.

A) Crops take the hit

Insect pests already cause big losses. One hard-published example is corn:

The Crop Protection Network estimated that 982 million bushels of corn were lost to corn invertebrates across reporting states in 2022, about 7.3% of the yield.

Here is the logic I connect to that:

If predators drop, more pests survive. When pest pressure rises, farmers spray more. When spraying rises, costs rise. Side effects rise too.

B) Chemical control rises

When natural predators fall, chemical control becomes the replacement tool.

In my text, I link that to:

• higher production costs
• pesticide runoff and water impacts
• harm to beneficial insects
• resistance escalation (with resistance reported across 550+ arthropod species, and resistance costs estimated in the billions)

You can debate exact dollar totals. The direction stays the same: less biology means more chemistry.

C) People feel it

More insects also change daily life:

• more mosquitoes and nuisance bugs
• less outdoor comfort
• more local control of spending
• more anxiety during disease outbreaks

My text cites a global mosquito-borne disease burden of about $12B/year. That is a reminder that insects are not a small issue.

Step 5: The money question

My text cites a key range from Boyles et al. (2011):

Bats provide pest-control value to U.S. agriculture of $3.7–$53B per year, with a commonly cited midpoint around $22.9B.

Even a small erosion of a service that large can translate into real costs for farmers.

My example also shows how someone could estimate marginal losses from turbine-related bat deaths. I treat that step as illustrative unless the national bat population input is anchored to a published estimate.

Bottom line

The cost of turbine wildlife mortality does not stop at the turbine base.

Using published mortality ranges and published consumption and valuation anchors, my conservative composite estimate is:

~1,300–2,500+ metric tons of insects per year are not consumed because of turbine-linked bird and bat deaths.

From there, the cascade is straight:

more surviving pests → more crop loss and more spraying → higher costs and wider ecological harm.

If wind energy seeks a full real-world accounting, I think it has to account for these downstream effects, not just megawatts and hardware.