Over the past several weeks, MM and his partner, the young sub-adult, have been seen mating at least five times, as observed by myself and neighbors. One neighbor commented, “they must be newlyweds.” In all matings observed, MM has assumed the dominant position so we think he must be the male. We hope the love birds are making lots of baby eaglets although, its not entirely clear whether or not a sub-adult is mature enough to produce eggs.
In thinking about tiny Piping Plovers and majestic Bald Eagles, it’s inspiring to know that conservation success measures, such as those taken to bring the Bald Eagle back from near extinction, are tremendously meaningful and impactful.
The below graph of Bald Eagle breeding pairs speaks a thousand words –
As the cat is out of the bag, so to speak (the Eagle’s location is being shared widely on social media platforms), the following is some information that may minimize further confusion and help folks better understand what is happening with the adult eagle and sub-adult eagle living in our midst.
The sub-adult appears to be about 3.5 to 4 years old and is un-banded. The adult (with the pure white head) was thought to have been banded at a north of Boston town (in 2015 or 2016) and is referred to as MM. Eagles get their “names” from the first two letters of the leg bands they received just before they fledged their nests.
The pair have been constructing a nest together. Is it unusual for an adult and sub-adult to bond and nest? Prior to live nest cams, ideas about Bald Eagle nesting and mating behaviors were more rigid. But much, much more is known now and it’s wonderfully captivating!
MM was perched when the sub-adult flew in. MM gave several loud croaky gull-like greetings. He/she assumed the dominant position and copulation took all of ten seconds (which is typical for birds!) MM dismounted and the pair stayed side-by-side together for sometime afterward.
Although MM took the dominant position, that does not mean he/she is a male. Female Bald Eagles also approach. Both male and females initiate bonding and both may assume a dominant position when bonding.
It’s also difficult to tell by observing. Eagles are sexually dimorphic, meaning the females are bigger than the males. To compare MM and his friend side by side, MM looks to be a bit smaller however, juveniles also appear a little bigger than adults due to longer feathers that help them fly more easily.
Bald Eagle MM and subadult, possibly 3.5 to 4 years of age
The return of American Bald Eagles to Massachusetts is a wonderful conservation success story. We now see Bald Eagle nests expanding throughout the state with overall numbers steadily rising each year. Several pairs are thought to now nest on Cape Ann!
By the turn of the previous century, the Bald Eagle had nearly disappeared from Massachusetts. Loss of habitat, hunting, trapping, and poison contributed to their demise during the 19th century. The last known nest was seen at Sandwich, Cape Cod in 1905. Nationwide, by the mid-twentieth century, the pesticide DDT nearly pushed the birds to extinction.
The Massachusetts Department of Fisheries and Wildlife (Mass Wildlife) now reports that as of January 2019, there are 76 territorial pairs, which is up from 68 pairs in 2017, and 59 pairs in 2016. From these 76 pairs, 65 chicks successfully fledged! How was this made possible?
In the early 1980s, it was discovered that some Bald Eagles were spending winters in the Quabbin Reservoir area. In 1982, MassWildlife, along with other organizations, including MassAudubon, began a project that would encourage nesting in the area.
Young eaglets from wild nests in Canada were reared in cages overlooking the Reservoir. This was done in hopes the eagles would view the area as home base and return to nest when mature.
The first fledged bird returned in 1989 and the Massachusetts Bald Eagle population has been steadily growing ever since! Forty-one chcks were raised using the “Hacking” method. Over 780 chicks have fledged since the program’s inception however this is likely an underestimation as the counts have largely centered around the Quabbin Reservoir, and most recently Lake Quinsigamond.
If you suspect a Bald Eagle nest in your area , please contact the State Ornithologist Andrew Vitz at andrew.vitz@mass.gov.
