The Unsolved Mystery of the Marbled Murrelet

The Unsolved Mystery of the Marbled Murrelet,” is from Hakai Magazine, which “explores science, society, and the environment from a coastal perspective.” It also recently was republished in High Country News.

“It was partially with the murrelets’ dire straits in mind that broad restrictions were placed on old-growth logging across 9.7 million hectares of federal land in the United States under the 1994 Northwest Forest Plan; individual states also curtailed the harvest on their lands to a lesser extent. In British Columbia, more than a quarter of nearly two million remaining hectares of suitable murrelet nesting habitat is on protected land.

“But the murrelets’ numbers haven’t climbed in response. The combined California, Oregon, and Washington population, with fewer than 20,000 individuals, continues to decline by as much as four percent per year. In British Columbia, where there may be closer to 100,000 murrelets, the population is declining by 1.6 percent per year. Even in Alaska, home to the greatest number of murrelets, scientists believe the population has declined by 71 percent since the 1990s, from around one million birds down to 270,000.”

Interesting points: “The terrestrial threats are as well understood as any, but marine threats are a complete mystery.”

And: “We strongly suspect that jays and crows can have a significant impact on murrelet eggs and chicks,” Rivers says. But why are jays and crows able to find the nests? It could be because the big trees murrelets use are too close to a forest’s edge, where jays and crows are more numerous. 


18 thoughts on “The Unsolved Mystery of the Marbled Murrelet”

  1. ..” has been on the water since 6:00 p.m., and has no qualms about getting a little more rest before the marbled murrelet comes aboard. As dictated by their permit, her team will have just under an hour to extract the little seabird’s story via measurements, blood samples, a leg band, and a radio tag. ” I’ve always wondered whether the manipulation of birds by scientists might have something to do with the problems of some rare birds. Calls that aren’t real calls, getting captured poked and prodded, and so on. It’s not too late to do the experiment.. pick populations that are similar for all other factors, and leave some alone. Come back in five years to check.

  2. @Sharon there has been research done on this, and for some species handling can have very bad consequences for the animals. In a case like this, though, where a relatively tiny number of birds are being handled, it’s not going to make much population-scale difference. (Which isn’t to say researchers shouldn’t find harmless ways of studying and tracking birds, just that it’s not likely contributing to the murrelets’ problems.)

    As to the “complete mystery” of marine threats … I dunno, seems like a dramatic decline of overfished small fish stocks — and the resulting boom-and-bust fluctuations of a population at the edge of collapse — would be a prime suspect, but evidently it’s easier to throw blame at crows and jays than say something that could be construed as critical of the fishing industry.

  3. I’m not a scientist, but since the climate is changing, wouldn’t it stand to reason that species that have historically been concentrated in cooler areas, would decrease or disappear? Has there been any attention to warmer climate species, are they improving?

    • Forester 353: “Has there been any attention to warmer climate species, are they improving?”

      In many ways the warmer climate plants (trees/shrubs, etc) are moving more north and considered invasive in their home range habitats. Eastern Red Cedar, Western Juniper appear to be on the increase as a result of climate disruption and moving into prairie areas. Now if Redwood, Ponderosa Pine or Douglas Fir were to respond in a similar way by moving into grasslands, the invasiveness would hardly be alarming, but rather something to celebrate. I’ve never understood why some bio-mass wood pellet producing industry doesn’t move in and harvest these demonized trees instead of those beautiful tall forests from the South. It’s seems like burning is a waster of a good viable product for profit. Then they could sell the pellets over there in North America instead of shipping them to this phony eco-green European crowd over here where I live. There’s just no clear answers by either the wood products side and the eco-enviro side doesn’t seem to have any either. Their only cry is humans are a plague on the earth and we need more science-based abortion, eugenics and assisted suicide programs to rid the planet of this plague so that Nature can heal itself. And if you think I’m exaggerating, go visit the transhumanist Genetic Literacy Project website where these are often topics of conversation. Naturally they never categorize themselves as part of that evil plague problem.

  4. I think the interior west fish people did an analysis of this, and targeted populations that were in areas more likely to stay colder for increased attention.

  5. @353 There’s ‘winners’ and ‘losers’ in climate change, but as far as the forage fish industry goes — on the east and west coast alike — climate change is a side note compared to the far greater impacts of humans removing billions of fish after eliminating most of their spawning habitat.

    There’s been some recent attempts to regulate forage fish overfishing. Hopefully it’ll work.

      • The articles don’t actually correlate to what you said. The oldest article from 2015 baiscally just says increases and decrease in various specie aren’t necessarily connected but its important to receive funding for these studies….hmmmm
        The second article from 2016 says that populations are actually improving, which would actually have the opposite effect on bird populations then is being seen.
        The last article sums it up that it is human population more than over fishing that is affecting forage fish.
        The only sure thing that I come away with is – I’m glad I’m not dependent on published papers for answers……..

        • “What they found was declines in some species and increases in others. Pacific herring and surf smelt, historically the two most abundant forage fish, declined by as much as two orders of magnitude in the most heavily populated areas of Puget Sound. Sand lance and three-spine stickleback increased across all four Puget Sound sub-basins examined, but these smaller fish species translate into less prey overall for larger fish, birds and marine mammals.”

          “… it’s easy to understand the recent dismay of many fisheries scientists, who have watched U.S. Pacific sardine numbers plummet as fishing has continued amid another natural downturn. In April, after documenting an estimated 90 percent decline in the stock — from an estimated 1.4 million tons in 2007 to roughly 100,000 tons today — the Pacific Fishery Management Council decided to close the sardine fishery. That moratorium takes effect July 1.”

          “While a couple areas of Puget Sound have seen herring increase, the fish have nearly disappeared from some spots south of Tacoma. […] The Cherry Point herring stock has declined since its peak in the 1970s. While there was once as much as 15,000 tons of spawning adults, scientists recorded a record low of only 372 tons in 2017. That is a 98 percent decline in biomass. ”

          I don’t think it makes sense to come away from these articles with a “some winners, some losers” takeaway … except maybe the last link on the Magnuson-Stevens “success,” but even that seems like a success only if the word is redefined to mean “not a complete mess.”

    • Didn’t your last link say that things are getting better re forage fish? Do you think that turnaround should have affected murrelet pops if that were a contributing factor to their decrease?

      • See that last reply above. As I understand it, forage fish populations are rebounding, but relative to a collapsed baseline. Still far, far below where they were just a few decades ago.

  6. humpbacks have been staying close to shore due to reduced fish stocks- likely due to climate change and its relationship to el nino and ocean acidification from increased carbon. I suspect that affects murrelet foraging as well. There are also more corvids (jays, ravens, and crows) than ever- you can look it up in the Breeding Bird Survey data- they are booming. So if they are important nest predators, that could be a big part of it.

  7. Continued loss and fragmentation of nesting habitat, especially on non-federal land + highly variable ocean conditions = not that surprising.

    • If you look at the historical nesting habitat at the early 1900’s, it was highly fragmented with numerous large stand replacement fires occurring along the PNW coastal range. The habitat has been improving for decades – on state lands in Oregon and Washington as these replacement stands have matured. Federal land containing suitable habitat has been essentially locked up for 20 years. I would think that the habitat is improving overall from the 70’s. What is the life span of a murrelet? Improving habitat over a couple of generations should lead to improving populations if the habitat was the limiting factor. If it is ocean conditions then we are back to “what is the effect of climate change?”

      • But even if climate change were to be (1) stopped and (2) reversed, other species have changed and filled in niches, and so we can’t go back.. I guess the key thing would be to know “is the reduction in bird numbers something we can manage reasonably or not? To me corvid killing programs or depopulating the area are not reasonable.

        • I think it’s ironic that we have the struggle with whether we should manage species even when it’s part of a natural cycle, yet at the same time argue that we should not manage our forests.

          • 353

            AMEN!!!! – You are one of many who has pointed out the irony of such positions here on this site. i.e. “My way is great but your’s stinks and I don’t need any evidence to go against long established and repeatedly validated science that you reference.”


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