Good fat, bad fat

A horde of hungry starlings have been visiting lately and they adore fatballs. I bought a deluxe fatblock with insects from Waitrose at the silly price of £3 and they demolished it in a day.

I noticed that lard was on sale in Waitrose for 33p and I wondered - would that be a cheaper and equal substitute. It is, after all, allegedly for human consumption.

I asked the charming young man what was the difference and he, quite rightly and not rudely, said that he didn't know as he was not a bird.

Neither am I. So I left it to the experts - and they seem happier with the cheaper version.

Is there a reason why it could do them any harm before I indulge their fancies again ?