5 replies to this topic

[RyanWarnerPa]

Since starting birding this spring I've noticed something about the Robins in my area. Their nest success rate is well bellow 75%, assuming that a nest success rate of 100% = four robins. Of the seven nests in my area that I was able to see and track accurately the breakdown looks like this.

2 nest had a 75% success rate. One nest only ever had 3 eggs and the other nest the fourth egg never hatched.

4 had a 50% success rate. All four had two unhatched eggs.

1 had a 0% success rate. The nest got blown out of the lilac bush.

There is an eighth nest that I can see but I haven't been able to look inside to count the eggs or the young so I excluded that from this data.

So my question is, what is the normal nest success rate for Robins?

[NatureLady]

I don't know the answer to your question, but I had a Robin's nest in my sister's garage that had two eggs in it and I never once saw a Robin near the nest. The other day I checked the nest and one egg was open and a dead bird inside and the other egg didn't hatch. I thought it was odd that the Robin wasn't laying on the eggs at night. Even though the weather is in the 70's and 80's at night.

[RyanWarnerPa]

Well from what I understand Robins will wait to incubate their eggs until all four are layed, this way they all hatch at the same time. If it was only two eggs in the nest and you never saw a robin attending to the nest I'd speculate that the mother met a tragic end before she could lay and raise.

[creeker]

All young birds have a high mortality rate. Parents just have to reproduce themselves once successfully, to maintain the population. Seems to me a lot of young robins leave the nest and are on the ground early, which leads to their demise.

[rogerVA]

Wikipedia sources a reference with: "Bird banders have found that only 25% of young Robins survive the first year."

[creeker]

Wikipedia sources a reference with: "Bird banders have found that only 25% of young Robins survive the first year."

And they're talking about the ones they've banded. Many never even make it that far. I'll bet from the point of hatching, it's more like 10-15%.