Nectar Sweetness Preference in Anna's Hummingbird (Calypte Anna)

Jeff Gartner, Wildlife Undergraduate Student

College of Natural Resources & Sciences

An investigation into the foraging preferences in Anna's Hummingbird

Nest Tree Selection of Swainson's and Red-Tailed Hawks in Butte Valley, CA

Cristina Portillo, Wildlife Undergraduate Student

College of Natural Resources & Sciences

We collected microhabitat data at nest trees to determine if Red-tailed Hawks and Swainson's Hawks showed a preference for certain tree characteristics. Microhabitat data included tree height, nest height, number of primary trunks, diameter at breast height, density of canopy, the presence or absence of lichen, lichen type, and local tree density. We used logistic regression to test the expectation that Red-tailed Hawks and Swainson's Hawks select older and larger trees relative to local availability. The implications of these results could inform which trees are selected for western juniper removal, which is an anticipated treatment conducted by the U.S. Forest Service in Butte Valley.

New Petrology and SEM imagery of the West China Peak Complex of the Ironside Mountain Batholith, Klamath Mountains, Trinity County, CA

College of Natural Resources & Sciences

The Ironside Mountain Batholith located in the Western Hayfork terrane in the Klamath Mountains province represents crustal derived plutonism that pre-dates the Nevadan Orogeny by 20Ma. Redating the Ironside Mountain Batholith will be done via U-Pb laser ablation of accessory zircons, this will yield an age of crystallization thus providing an age of emplacement, and constrain the pre-Nevadan orogeny. Barnes and Petersen dated the Ironside Mountain Batholith in 1992 using U-Pb, Pb-Pb, and K-Ar dating methods, and yielded a date in the Mid Jurassic from 169 Ma (K-Ar) to 174 Ma (U-Pb), with an accepted age of 170Ma.

Northern Harrier Foraging Modes in Habitats Around Humboldt Bay

Collin Silva, Wildlife Undergraduate Student

College of Natural Resources & Sciences

Northern harriers are generalist predators known to occupy and forage over a variety of wetland and grassland types in North America. Whether Northern harriers adapt their foraging modes over different habitat types to maximize their success and energy intake is not known with any confidence. This study addresses this knowledge gap on a small scale around Humboldt Bay at various wetland and grassland sites.

Nourishing Community Health

Levit Cantu, Biological Sciences Undergraduate Student

College of Natural Resources & Sciences

Open Door Health Centers is a nonprofit community clinic that provides affordable, accessible healthcare to underserved populations. As a College Corps Fellow, I work with the Member Services department, specifically supporting gardens and food resources. My role focuses on increasing access to fresh, healthy food through community garden initiatives and resource navigation. This experience has allowed me to support food security efforts while gaining insight into the intersection of health, nutrition, and community service.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

The Gravity Lab at Humboldt State is concerned with measuring the force of gravity at unprecedented distance scales. Theories new and old make predictions about how gravity should behave, but accurate measurements of gravitational forces between objects close together have remained challenging. The crux of the experiment lies in sufficiently silencing the non-gravitational forces acting at the measuring site, and accomplishing this requires applying at least a little knowledge from most undergraduate physics classes. The implications of progress in this lab make it exciting to a general audience while remaining beneficial from an undergraduate learning perspective.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

Inconsistencies between Quantum Mechanics and General relativity have motivated many new theories which unify these two very successful models of physics. Many of these theories predict changes to the behavior of gravity at the sub 50 micron distance scale, specifically deviations from the newtonian Inverse Square Law (ISL) and Weak Equivelance Principle (WEP). We measure the twist of the torsion pendulum as an attractor mass is oscillated nearby in a parallel-plate configuration, providing a time varying torque on the pendulum. The size and distance dependence of the torque variation provides a means to determine any deviation from the WEP or ISL at untested scales.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

Physical processes regarding gravity are well understood on the scale of planetary distances but pose challenges in measurements at very short distances. Theories such as the Inverse Square Law (ISL) and Einstein’s Weak Equivalence Principle (WEP) of General Relativity have been tested over distance scales from 1 cm to infinity [1]. Reliable measurements of gravitational forces at scales smaller than a centimeter carry significant challenges. The non-gravitational forces that are generally negligible at the scale of everyday objects have a much more substantial effect in the sub-centimeter regime. Our experiment seeks to measure gravity at these close distances.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

Due to inconsistencies between General Relativity and the Standard Model, tests of gravity remain at the forefront of experimental physics. At HSU, undergraduates and faculty are designing an experiment sensitive enough to detect gravitational interactions below the 50 micron scale. The experiment measures the twist of a torsion pendulum as an attractor mass is oscillated nearby in a parallel plate configuration, providing time varying gravitational torque on the pendulum. The size and distance dependence of the torque variation will provide a means to determine any deviation from current models of gravity on untested scales.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

Gravity has been tested rigorously at distance scales from 1cm up to astronomical distances. The experiment being run in Humboldt State Universities Gravity Lab seeks to test gravity at previously untested distances below the centimeter level. To do this, a pendulum is suspended by a torsion fiber and oscillates in front of a movable mass. By moving the mass back and forth, one can measure a gravitational force on the pendulum by looking at the twist in the fiber. The data from the pendulum are then compared with well established theories of gravity to see if the accuracy of the theories at large distances translates to smaller scales.