What's on the menu at the Decorah North Nest?

Kike collected prey remains from the Decorah North nest when we were working on cameras in the fall of 2017. Since my family was tired of animal parts in the garage and 2018's fall camera work is just around the corner, I decided it was time to get them identified!

The photo below shows all of the remains that Kike recovered from the nest. In all, he found 23 white-tailed deer remains (4 partial skulls, 18 leg bones, including four with the hooves still hatched, and one sacrum that measured 3-7/8" wide by 7.5" long), three wild turkey remains (legs with the claws still attached), one opossum skull, one raccoon skull, an unknown set of wings, a dry corncob, 4 unknown vertebrae, 1 unknown skull fragment, and some unknown mammalian leg bones. We also found some miscellaneous clods of fur that looked like white-tailed deer fur given the color, texture, and size of the fur piles. These were not included in our count.

I was really surprised that we didn't find more fish remains! Sherri Elliott provided this list of menu items from the 2017 North Nest season:

Feathered (19) Birds (6) Chicken and parts (4) Coot (2) Duck (1) Gosling (2) Grouse or Pheasant (3) Turkey or Goose (1)	Finned (246) Trout (144) Sucker (44) Fish pieces (58)
Furred (47) Deer – Heads (4)  Legs or sections (12)  Groundhog or Muskrat (2) Oppossum (2) Rabbit (8) Raccoon and pieces (11) Squirrel (6) Field Mice or Voles (4)	Reptiles (2) Turtles (2) Miscellaneous (125) Cow Placenta (37) Mystery Meat or Unidentified Food Objects (48) Animal legs/feet (4) Pink/Red Innards (24) Bony Meat (12)

What we saw come into the nest was in line with our expectations about what eagles eat overall.  As we've seen in our other nests, the North Eagles have a preference for fresh fish but will happily eat other foods, especially if those foods fall into the low risk/high reward category - think cow placenta, which takes very little energy expenditure or risk to get when cows are calving near your nest tree. However, if we had been relying on nest remains to determine eagle diet, we would have had a very distorted view of their food web. The prey remains we find in a nest might not adequately reflect what the eagles are eating, especially if they are eating foods that don't leave prey remains behind (placenta, innards), decompose quickly or fall into the nest (small or previously butchered prey), or are eaten by nest visitors like mice, squirrels, and other birds.

Having said that, I was surprised by all of the white-tailed deer. We've been asked about it several times. Were the deer killed by a combine? Were the deer road-killed? Are the eagles preying on live fawn deer? What's up with all the deer?

To solve the puzzle, we have to start with the season. Mr. and Mrs. North were bringing in fawn deer between April and mid-May. Combines aren't used for discing, planting, or early cultivation, which rules out combine-killed deer. There aren't a lot of hay fields in the area and it is also too early for haying. How about road-kill? We can't rule it out entirely, but the area doesn't have many roads or much traffic, and the whole legs and sacrum were not smashed, broken, or splintered, something I would expect to see in road-killed deer. Many of the deer parts were also fairly well-developed, with small black hooves and/or bits of fur still clinging to them, which rules out aborted fetal deer.

Were Mr. and Mrs. North predating fawn deer? We used to assume that any deer brought into the nest were scavenged, but bald eagles have been observed predating fawn deer. In 2011, naturalists documented predation of a radio-collared white-tailed fawn in Menominee County, MI. In 2016, biologist Sophie Gilbert documented bald eagle predation of Sitka Black-tailed fawns. In 2017, a landowner in northeastern Wisconsin witnessed an eagle attack and kill a swimming fawn. Once the fawn was dead, the eagle dragged it to land and began feeding. In other words, it is possible that Mr. and Mrs. North were preying on fawn deer, not simply finding them dead.

The documented research on eagle/fawn deer predation tends to indicate that eagles don't commonly predate deer, so why are Mr. and Mrs. North bringing so many deer to the nest? While four or five deer (based on skull count, leg count, and observation) isn't a whole lot of deer either population or percentage-wise, it is more deer than were documented in Gilbert's study or the study done in Michigan. A few thoughts:

• Eagles know their territories and their prey. It wouldn't take Mr. and Mrs. North long to learn that fawn deer are vulnerable to predation, especially during the first three to four weeks of life. While the Norths prefer fish over everything else, they would be happy to take an animal with a lot of reward for very little risk. 
• There are a lot of deer in the valley of the Norths. The river, grasslands, and upland forests are surrounded by row-cropped corn and beans. This concentrates deer (and many other animals) along the river's corridor. Predated or scavenged, the presence of deer in the North's diet might be a function of the sheer numbers of deer in the valley. 
• The Norths have an excellent territory in which to find and predate fawn deer. Their forests are relatively open, reducing the amount of cover for fawns to shelter in. Deer often cross the broad, open valley for water and forage, putting young fawns at risk once they begin traveling with their mothers. 

What did we learn? The North nest prey remains did not accurately reflect the North's overall diet, but still yielded some interesting surprises! Given the scarcity of data on eagles predating fawn deer, we'll be looking into this issue more deeply. I'm also curious about the lack of opercular bones given all the trout and suckers that were brought into the nest. We found them in the Fort St. Vrain nest. Why aren't they here?

Did you know? Bonus Skull!
Teeth are my best friend when it comes to skull identification. The skull below is upside down. Our mystery animal has some pretty unique teeth. Its combination of sharp front teeth and molars for grinding mark it as an omnivore. How many front teeth does it have past its sharp canines? It's hard to see here, but I counted ten. This marks it as an opossum! Opossums have 50 teeth total - more than any other North American land mammal! https://en.wikipedia.org/wiki/Virginia_opossum

Links

• North eagles eat baby deer: https://youtu.be/iL5YPXSn04o. Watchers might find this video upsetting. Mrs. North brings in a partial fawn deer and the eaglets consume it. While we don't know how the deer died, it still has some grass in its stomach. White-tailed deer begin foraging at around two weeks of age. 
• Swimming fawn falls prey to bald eagle (watchers might find this upsetting):
  https://youtu.be/Olclpfjn2hU
• Bald eagle predation on Sitka black-tailed deer fawns:
   https://pdfs.semanticscholar.org/b8bf/fd34493b06397b44d7d1c59b564b00f61465.pdf
• Bald eagle predation of a white-tailed deer fawn:
   http://www.bioone.org/doi/abs/10.1656/045.018.0108

Birds Threatened By Proposed Rollback Of Endangered Species Act Protections

Imagine a world where there were no bald eagles or peregrine falcons. By the late 1960's, rampant use of the pesticide DDT, habitat loss, and persecution made extinction seem very likely. The Endangered Species Act (ESA), signed into law by President Nixon in 1973, was an important part of bald eagle and peregrine falcon recovery. It:

• Levied serious legal penalties for killing threatened and endangered species;
• Mandated the preservation of habitat critical to a listed species' survival, and;
• Decreed that federal agencies prevent their actions from jeopardizing the existence of threatened and endangered species. 

Despite overwhelming public support for the Act, the U.S. Department of the Interior is currently proposing to roll back endangered and threatened species protections in three critical areas. Their changes will:

• Roll back habitat protection for endangered and threatened species; 
• Reduce protections for and allow take of threatened species, and;
• Weaken the role that biological assessment and science play in listing decisions.

Federal rule changes require a period of public input, which in this case ends on September 24th. If any of you would like to comment, we've put together a breakdown of the proposed changes, what each change actually means when stripped of its bureaucratic language, and links to comment. The changes break down like this...

Critical Area I: Rolling back habitat protection for endangered and threatened species
Revision of the Regulations for Listing Species and Designating Critical Habitat. This proposed rule change will make it harder to designate critical habitat: the land and waters that endangered and threatened species need to survive. It will also make it easier to eliminate existing critical habitat, opening previously protected land to commercial and recreational use.

• What it says: "We propose to revise section 424.12(a)(1) to set forth a non-exhaustive list of circumstances in which the Services may find it is not prudent to designate critical habitat as contemplated in section 4(a)(3)(A) of the Act. Under the clarifications that we propose in this revision, the Services would have the authority but would not be required to find that designation would not be prudent in the enumerated circumstances."
• What it means: 4(a)(3)(A) requires the Service to designate critical habitat when it makes an endangered or threatened listing; i.e., when a species is listed, its habitat must also be listed. The proposed rule change would allow the Service to exempt habitat from the listing.
• Why it's important: For endangered species, critical habitat is the key to survival. A study by the Center for Biological Diversity found that plants and animals with federally protected habitat are more than twice as likely to be moving toward recovery than species without it. Migratory species like birds are especially vulnerable to habitat destruction because they tend to inhabit more than one natural habitat. This seemingly innocuous proposal eliminates one of the most important tools we have to protect and rebuild species in danger of going extinct. If species don't have a place to live, migrate, feed, and breed, listing means little to nothing.

What you can do: Comment on this change by pressing the blue "Comment now" button at the upper right side of this page: https://www.regulations.gov/document?D=FWS-HQ-ES-2018-0006-0001.

The devil in the details: The federal government seeks feedback on whether it should consider modifying the definitions of “geographical area occupied by the species” or “physical or biological features” in Section 424.02. The geographical area is currently defined as an area that may generally be delineated around species' occurrences. This may include those areas used throughout all or part of the species' life cycle, even if not used on a regular basis (e.g., migratory corridors, seasonal habitats, and habitats used periodically, but not solely by vagrant individuals). The physical or biological features are the features that support the life-history needs of the species, including but not limited to, water characteristics, soil type, geological features, sites, prey, vegetation, symbiotic species, or other features - including critical ephemeral locations like migratory feeding, wintering, or summering grounds. Changing these definitions could have a significant negative impact on habitat conservation.

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Critical Area II: Rolling back legal protection for threatened wildlife and plants
Revision of the Regulations for Prohibitions to Threatened Wildlife and Plants. This proposed rule change will reduce legal protection for wildlife and plants listed as threatened.

• What it says: "We, the U.S. Fish and Wildlife Service, propose to revise our regulations extending most of the prohibitions for activities involving endangered species to threatened species. For species already listed as a threatened species, the proposed regulations would not alter the applicable prohibitions. The proposed regulations would require the Service, pursuant to section 4(d) of the Endangered Species Act, to determine what, if any, protective regulations are appropriate for species that the Service in the future determines to be threatened."
• What it means: "Take protection" was extended to threatened species in 1978. Like endangered species, threatened species can't be harassed, harmed, pursued, hunted, shot, wounded, killed, trapped, captured, or collected. It provides safeguards to species that are in need of support, but allows some activities to be exempted if the Service finds it appropriate. The proposed rule change would remove these protections for species listed as threatened.
• Why it's important: Section 4(d) provides legal protection and resources to threatened or dwindling species while rewarding collaborative conservation efforts to keep species like the Gunnison Sage Grouse off the endangered species list. Rolling back these protections will allow threatened wildlife and plants to be subject to "take". It will also remove incentives for collaboration, making it more difficult and costly to reverse population declines. The Section 4(d) rule was designed to create fewer endangered species by providing incentives to protect and rebuild threatened species. Rolling it back will cause population declines among wildlife and plants already struggling to hold on, creating more endangered species.

What you can do:  Comment on this change by pressing the blue "Comment now" button at the upper right side of this page: https://www.regulations.gov/document?D=FWS-HQ-ES-2018-0007-0001

The devil in the details: The federal government seeks specific feedback about replacing blanket 4(d) protections with special rules for each species listed as threatened. It also seeks feedback regarding a timeframe for finalizing any rules, after which the rule would be dropped and the process restarted before any decision could be made. Replacing blanket protections with special protections and drop rules will significantly reduce protections for threatened species, especially given the dwindling resources allocated to the Fish and Wildlife Service.

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Critical Area III: Weakening the role that biological assessment and science play in listing decisions
Revision of Regulations for Interagency Cooperation. This proposed rule change will weaken the role that biological evidence and science play in listing decisions.

• What it says: "We, FWS and NMFS (collectively referred to as the “Services” or “we”), propose to amend portions of our regulations that implement section 7 of the Endangered Species Act of 1973, as amended. The Services are proposing these changes to improve and clarify the interagency consultation processes and make them more efficient and consistent."
• What it means: The Endangered Species Act currently directs all Federal agencies to work to conserve endangered and threatened species and to use their authorities to further the purposes of the Act. The proposed changes to Section 7 weaken the requirement that Federal agencies consult with the U.S. Fish and Wildlife Service when any action an agency carries out, funds, or authorizes may affect a listed endangered or threatened species.
• Why it's important: When a Federal agency determines that its action is likely to adversely affect a listed species, the agency submits a request for formal consultation to the Fish and Wildlife Service. Formal consultation includes sharing information about the project and species likely to be affected by the action. Once formal consultation is done, the Service prepares a biological opinion on whether the proposed activity will jeopardize the continued existence of a listed species. The Section 7 Rule mandates consultation and produces listing decisions based on the best available biological science. Rolling it back will reduce the role that science-based evidence plays in making listing decisions and minimize the role of the US Fish and Wildlife Service in conserving America's wildlife and plants for the public good.

What you can do:  Comment on this change by pressing the blue "Comment now" button at the upper right side of this page: https://www.regulations.gov/document?D=FWS-HQ-ES-2018-0009-0001.

The devil in the details: Note that the federal government is seeking comment on the extent to which the changes outlined in this proposed rule will affect timeframes and resources needed to conduct consultation and (2) anticipated cost savings resulting from the changes. They are also seeking comment on the merit, authority, and means for the Services to conduct a single consultation, resulting in a single biological opinion, for Federal agency actions affecting species that are under the jurisdiction of both FWS and NMFS. FWS has a higher standard.

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According to the proposed rule changes, the federal government seeks only to make things more efficient and streamlined. Their concentration on technical definitions, bureaucratic language, and efficient timeframes conceals their true intent - to drastically roll back protections for endangered and threatened animals and plants and the habitat they live, feed, breed in, and move through. If I didn't find it all so appalling, I might be awed by the sheer nefariousness of this death by a thousand cuts. Follow the comment links earlier in this blog to speak up for America's wildlife and wildlands.

Opponents of the Endangered Species Act sometimes argue that the law hasn't been successful, but according to a 2016 report published by The American Bird Conservancy, seventy-eight percent of mainland birds listed as Threatened or Endangered under the ESA have populations that are now stable, increasing, or have recovered enough to be delisted. That sounds an awful lot like success to me.

Why do I care? I had the privilege of visiting Chicago's Field Museum during a peregrine conference five years ago. Attendees were given a behind-the-scenes tour of the museum, including a look at their vast bird collection - lovingly preserved corpses of birds kept for study and remembrance. It was there that I got my only look at the Carolina parakeet and the Ivory-billed woodpecker. Gone forever from life, the two species now exist only as study skins in museums. Had the United States not banned DDT and passed the Endangered Species Act, it is highly likely that peregrine falcons, bald eagles, and many other animals would have joined them, existing only as rumors, museum specimens and curiosities on film. However cherished their memories or lovingly preserved their corpses, they too would be gone, dead, extinct, lost. Forever. I care because I've come to love them, and because I also believe that their survival is our own. This land is our land. We need to care for it and respect it.