Here’s a sample study, that is commonly referenced, to show how deadly lead shot is..
Lead shot ingestion by mourning doves on a disked field
Abstract
Previous field studies of hunter-harvested mourning doves (Zenaida macroura) have reported the percentage of birds with ingested lead shot as 0.2–6.5%. To reduce the uncertainty concerning the number of doves that ingest shot, we conducted an experiment to test the proportion of mourning doves that ingested lead shot on the bare soil of a disked field (typical of a managed dove field) to simulate more natural feeding conditions. In each of 3 treatment groups of 80 birds, we exposed 35 birds to low-density lead shot (1.5 million shot/ha), and 35 birds to high-density lead shot (29.5 million shot/ha), and 10 birds served as controls (no shot). We dosed 5 positive control birds with 2 lead shot each in trials 2 and 3. We scattered lead shot and mixed seed on the loosely packed soil of treatment cages and after 4 days of exposure, 2.9% of doves voluntarily ingested ≥1 lead shot. The proportion of birds that ingested shot when exposed to the high-density shot treatment (4.9%) was not different (P = 0.098) from that of the low-density shot treatment (1.0%). Lead concentrations in liver, kidneys, and blood reached maxima of 94.402 ppm, 346.033 ppm, and 13.883 ppm wet mass, respectively. Differences in delta-aminolevulinic acid dehydratase (ALAD) activity, packed cell volume, and heterophil:lymphocyte ratio (H:L) were greater posttreatment in doves that had ingested shot than in those that did not. The risk posed to mourning doves from lead shot ingestion can be reduced by banning lead shot on management areas or dove fields or disking fields after hunting season to reduce shot availability. © 2011 The Wildlife Society.
And here’s my analysis of it..
1 oz. #7-1/2 (338 pellets) is a typical “dove load”
en.wikipedia.org
1ha = 10,000 square meters..an area of 100m x 100m..or to visualize..about 2.5 football fields side-by-side.
Low study shot density..1.5 million shot/ha..or 150 shot per square meter
To reach this density there would need to be 4,438 discharges of 1oz “dove loads” or 178 boxes of 25/box dove loads
So about a half of a load of #7-1/2 shot per square meter at the low study shot density.
High study shot density..29.5 million shot/ha..or about 2,950 shot per square meter
To reach this density there would need to be 85,799 discharges of 1oz “dove loads” or 3,432 boxes of 25/box dove loads at ~$20 each..or $68,640..about what a normal hunter shoots over their 100mx100m dove food plot during the 30 day dove season.
So about a 9 rounds of #7 1/2 shot per square meter at the high study shot density..or about 2 #7-1/2 shot per square inch
Are those really realistic shot densities? C’mon man!!
Dove trapped in cages for 4 days and only 2.9% ingested more than 1 shot at the “low” shot density..and only 4.9% ingested more than 1 shot at the “high” density.
2.9% of 35 birds is 1 bird. So, only 1 bird in the entire cage voluntarily ingested ≥1 bird-shot. Keep in mind these are trapped birds. The control birds were force-fed 2 pellets.
Cage size not specified in the study abstract..but 35 birds in a cage of unknown size.
Birds don’t intentionally ingest round stomach stones to grind the seeds in their crop. Round stones are not as effective as rough or sharp stones in grinding seeds. Round stone are regurgitated from the crop because they’ve been ground smooth and do not function as well as the rough ones. So you’d have to ask yourself, why would caged birds ingest lead shot? Was that all that was on the cage “floor” for them to utilize as stomach stones?
Since 1991, a Federal ban on the use of lead shot in hunting migratory birds has been in effect…BTW