Wednesday, April 13, 2011

To Move/Remove the Eggs or Not To Move/Remove the Eggs?

There are many viewers anxiously watching and waiting for this nest to progress and with that comes suggestions and questions about intervening. Two popular thoughts are emerging: either move all of the eggs together into one scrape; or remove the 2 eggs from the right scrape from the nestbox completely. The third option is to do nothing. Before that decision can be made there are a lot of different factors to consider:

I will stress again that the behaviors and circumstances we are witnessing in the Rhodes Tower nest this year are completely normal for a first time nesting pair of peregrine falcons. I have watched Durand’s actions with the now 3 eggs in the left scrape and can say that even if the other 2 eggs were removed from the nest (or were included with the others so they were all in one scrape) her incubation behavior at this point is sporadic at best – she is off the eggs, on the eggs, and covering some of the eggs, but not all of them at all times. She is leaving the nestbox frequently and perching nearby. These fidgety actions are definitely not typical incubation behavior. We do not know if she will get the “hang of it” or not. Her ability to get the proper incubation technique perfected is dependent on her hormone levels and that is a factor completely separate of how many eggs are underneath her or elsewhere in the nestbox. The “abnormal” events of eggs in different scrapes and intermittent incubation that we are witnessing is a direct reflection of her lack of maturity and inexperience and again, that is normal, given her age.

Besides Durand incubating in proper form, another factor for this nest to be successful is the participation of the male. The male is likely a first time nesting bird as well and thus he also lacks experience and maturity. It will take time for his instincts to kick in properly as well. Even though he has been providing food for Durand, for the eggs to hatch successfully he will have to assume some of the incubation duty. Unfortunately so far he has not shown any indication to do so.

What about moving all the eggs together? Consider that if all 5 eggs were in the same scrape it could result in less efficient incubation for this young, inexperienced bird (provided she starts to incubate as she should). So perhaps it is better that she has fewer eggs to cover then more? Keeping 5 eggs properly incubated for 32 days would be a challenge for even the most experienced female.

Other thoughts to consider with moving (or removing) the 2 eggs: Intervening with good intentions could have unanticipated bad results. What if after moving/removing eggs the nest was abandoned (a very real possibility with a first-time nesting pair)? Or some or all of the eggs did not hatch? Or one or more eggs were damaged in the process? Or an adult was injured trying to defend the nest? No action is without a reaction and even though humans have in mind what we think is best, other unanticipated and potentially very negative results could occur.

Given all of these “what ifs” we must also consider the current status of the population being what it is. The return of the peregrine falcon has been a Wildlife Management success story! There are now way MORE falcons nesting throughout the Midwest then ever before. That is not even to count how many “surplus” falcons are out there ready to take over a territory when there is a vacancy. Perhaps 10, but certainly 20 years ago we would likely have intervened because the population was so low at that time that the extra help was needed to continue the recovery efforts and possible negatives would have been worth the risks. But now we are beyond recovery of the peregrine population and so the need for each and every egg to have the best chance does not apply.

Biologists manage wildlife populations as a whole. Except in the case of an endangered species, individuals actually play a very small role in the big picture of the health and sustainability of overall populations. That can be a hard concept for some to realize and accept—especially when webcams allow us to focus so much on specific individuals. Albeit difficult we must all keep in mind that nowhere in nature does any bird species have 100% success with a nest. As many as 8 out of 10 birds do not make it through their first year.

This is an issue with many different opinions. Given all of the facts, the Division of Wildlife’s standpoint is to not intervene in this situation. Ultimately, it will be up to Durand and the male to sort this one out. We can only stand to learn as we witness how this plays out.