boils down to this. He wants to know how many acorns a pigeon can stuff into its crop. Big acorns, in this case, for the season produced the most magnificent specimens he had seen in more than thirty years. He has ruled out other predators. There were no badgers about in the area at the time. Squirrels hadn't been seen for decades. It has to be the birds, and pigeons were the prime suspects. And yet, two barrowloads of these acorns had laid at the foot of a tree for weeks, and only when the few days of very hard weather came in, did the pile diminish. One day they were still heaped high, forty eight hours or so later, there was a thin enough covering of them on the ground. Then, overnight, or early in the morning, there wasn't one acorn to be seen.
hooting folk will have heard or read about pigeons so heavily laden in the crop, that they could hardly rise from the ground. Indeed there was a query in an Old Field book of country questions about one shot pigeon which was found to have eighteen large acorns in its crop. And some of them were germinating. The writer wants to know if they germinated in the bird's crop or were they already germinating when swallowed. The solemn answer was that germination even under the most favourable circumstances, takes several days with acorns, although once the radicle or first rootlet breaks out, it develops quickly. Unlikely, then, that the germination took place within the crop. The pigeon clearly ate those acorns that were already sprouting. But of course, some further development might have taken place in the crop it was admitted. A bit prissy, that answer.
But back to the original question. A comparison might be made, and an estimate come to, when you read that story in White's Selbourne, where a wood pigeon shot at dusk, was found to have its craw stuffed with "the most nice and tender tops of turnips," enough, when washed and cooked to provide "a delicate plate of greens" for shooter and wife.